|
1
|
Sharma P, Abbey D. Alagille Syndrome: Unraveling the Complexities of Genotype-Phenotype Relationships and Exploring Avenues for Improved Diagnosis and Treatment. Cell Biol Int 2025; 49:435-471. [PMID: 40042123 DOI: 10.1002/cbin.70009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 02/03/2025] [Accepted: 02/16/2025] [Indexed: 04/15/2025]
Abstract
Alagille syndrome (ALGS) is a rare genetic disorder caused by mutations in the JAG1 and NOTCH2 genes, leading to a wide range of clinical manifestations. This review explores the complex genetic and clinical landscape of ALGS, emphasizing the challenges in understanding genotype-phenotype relationships due to its rarity and the lack of suitable research models. The review projects a clinical overview of the disease, emphasizing the influence of potential gene modifiers on its clinical presentation and the lack of mechanistic studies for over 100 mutations identified in the last 24 years from various populations, representing a significant gap in our current knowledge and advocating for further exploration. The review addresses the diagnostic challenges posed by the variable expressivity and overlapping symptoms of ALGS. It summarizes current treatment options and discusses emerging approaches such as antisense oligonucleotides (ASOs) and gene therapies. Further, the need for improved diagnostic tools, a deeper understanding of the underlying mechanisms, and the development of targeted therapies are emphasized using zebrafish and mice models, as well as genome editing for variant analysis and stem cell organoid models for disease modeling and drug discovery. The importance of cohort-based studies in understanding the natural history and outcomes of ALGS in diverse populations is highlighted. The review concludes by emphasizing the need for multi-disciplinary collaborative research to address the challenges in ALGS diagnosis, prognosis, and treatment, particularly for underrepresented populations.
Collapse
Affiliation(s)
- Priya Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Delhi, India
| | - Deepti Abbey
- Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Delhi, India
| |
Collapse
|
|
2
|
Lin Q, Tam PKH, Tang CSM. Genetics of biliary atresia: Approaches, pathological insights and challenges. Semin Pediatr Surg 2024; 33:151477. [PMID: 39862688 DOI: 10.1016/j.sempedsurg.2025.151477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2024] [Accepted: 01/07/2025] [Indexed: 01/27/2025]
Abstract
Biliary atresia (BA) is a severe neonatal cholestatic disorder marked by fibro-obliteration of the extrahepatic and intrahepatic bile ducts. It is the most common cause of pediatric end-stage liver disease and the leading indication for liver transplantation in children. There is significant heterogeneity in the etiology, involving various genetic and environmental factors such as viral infection, immune dysregulation and genetic predisposition to defective hepatobiliary development. In this review, we discuss the strategies to uncover the genetic factors underlying BA and highlight their associated molecular and pathological mechanisms, as well as the challenges faced in this area of research.
Collapse
Affiliation(s)
- Qiongfen Lin
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Paul Kwong-Hang Tam
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; Precision and Regenerative Medicine Research Centre, Medical Sciences Division, Macau University of Science and Technology, Macao, China.
| | - Clara Sze-Man Tang
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; Dr Li Dak-Sum Research Centre, The University of Hong Kong - Karolinska Institutet Collaboration in Regenerative Medicine, Hong Kong, China.
| |
Collapse
|
|
3
|
Bai MR, Pei HY, Zhou Y, Song HL, Pan WH, Gong YM, Wu WJ, Yu WW, Cui MM, Gu BL, Chu X, Cai W. Association analysis and functional follow-up identified common variants of JAG1 accounting for risk to biliary atresia. Front Genet 2023; 14:1186882. [PMID: 37255715 PMCID: PMC10225652 DOI: 10.3389/fgene.2023.1186882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/05/2023] [Indexed: 06/01/2023] Open
Abstract
Background: Biliary atresia (BA) is a destructive, obliterative cholangiopathy characterized by progressive fibro-inflammatory disorder and obliteration of intra- and extrahepatic bile ducts. The Jagged1 (JAG1) gene mutations have been found in some isolated BA cases. We aim to explore the association of common variants in JAG1 with isolated BA risk in the Chinese Han population. Methods: We genotyped 31 tag single nucleotide polymorphisms covering the JAG1 gene region in 333 BA patients and 1,665 healthy controls from the Chinese population, and performed case-control association analysis. The expression patterns of JAG1 homologs were investigated in zebrafish embryos, and the roles of jag1a and jag1b in biliary development were examined by morpholino knockdown in zebrafish. Results: Single nucleotide polymorphisms rs6077861 [P Allelic = 1.74 × 10-4, odds ratio = 1.78, 95% confidence interval: 1.31-2.40] and rs3748478 (P Allelic = 5.77 × 10-4, odds ratio = 1.39, 95% confidence interval: 1.15-1.67) located in the intron region of JAG1 showed significant associations with BA susceptibility. The JAG1 homologs, jag1a and jag1b genes were expressed in the developing hepatobiliary duct of zebrafish, especially at 72 and 96 h postfertilization. Knockdown of both jag1a and jag1b led to poor biliary secretion, sparse intrahepatic bile duct network and smaller or no gallbladders compared with control embryos in the zebrafish model. Conclusion: Common genetic variants of JAG1 were associated with BA susceptibility. Knockdown of JAG1 homologs led to defective intrahepatic and extrahepatic bile ducts in zebrafish. These results suggest that JAG1 might be implicated in the etiology of BA.
Collapse
Affiliation(s)
- Mei-Rong Bai
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Hao-Yue Pei
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Ying Zhou
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Huan-Lei Song
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Wei-Hua Pan
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yi-Ming Gong
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wen-Jie Wu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wen-Wen Yu
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Meng-Meng Cui
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Bei-Lin Gu
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Xun Chu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Wei Cai
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai Institute of Pediatric Research, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| |
Collapse
|
|
4
|
Li J, Wu H, Chen S, Pang J, Wang H, Li X, Gan W. Clinical and Genetic Characteristics of Alagille Syndrome in Adults. J Clin Transl Hepatol 2023; 11:156-162. [PMID: 36406308 PMCID: PMC9647109 DOI: 10.14218/jcth.2021.00313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/26/2021] [Accepted: 03/06/2022] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND AND AIMS Alagille syndrome (AGS) is an autosomal dominant multisystem disorder caused by mutations in the JAG1 and NOTCH2 genes. AGS has been rarely reported in adult patients, mainly because its characteristics in adults are subtle. The study aimed to improve the understanding of adult AGS by a descriptive case series. METHODS Eight adults diagnosed with AGS at our hospital between June 2016 and June 2019 were included in the study. Clinical data, biochemical results, imaging results, liver histopathology, and genetic testing were analyzed. RESULTS Three female and five male patients with a median age of 24.5 years at the time of diagnosis were included in the analysis. The clinical manifestations were adult-onset (62.5%, 5/8), cholestasis (50%, 4/8), butterfly vertebrae (62.5%, 5/8), systolic murmurs (12.5%, 1/8), typical facies (12.5%, 1/8), posterior embryotoxon, and renal abnormalities (0/8). Genetic sequencing showed that all patients had mutations, with four occurring in the JAG1 gene and four in the NOTCH2 gene. Six were substitution mutations, one was a deletion mutation, and one was a splicing mutation. Five had been previously reported; but the others, one JAG1 mutation and two NOTCH2 mutations were unique and are reported here for the first time. CONCLUSIONS The clinical manifestations highlighted by the current diagnostic criteria for most adults with AGS are atypical. Those who do not meet the criteria but are highly suspicious of having AGS need further evaluation, especially genetic testing.
Collapse
Affiliation(s)
- Jianguo Li
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Haicong Wu
- Department of Hepatobiliary Medicine, 900th Hospital of Joint Logistics Support Force, Fuzong Clinical Medical College of Fujian Medical University, Fuzhou, Fujian, China
| | - Shuru Chen
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jiahui Pang
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Heping Wang
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xinhua Li
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Weiqiang Gan
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Key Laboratory of Liver Disease Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| |
Collapse
|
|
5
|
Sergi CM, Gilmour S. Biliary Atresia: A Complex Hepatobiliary Disease with Variable Gene Involvement, Diagnostic Procedures, and Prognosis. Diagnostics (Basel) 2022; 12:330. [PMID: 35204421 PMCID: PMC8870870 DOI: 10.3390/diagnostics12020330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/24/2022] [Indexed: 02/04/2023] Open
Abstract
The diagnosis of biliary atresia is still terrifying at the 3rd decade of the 21st century. In a department of neonatal intensive care unit, parents and physicians face a challenge with a jaundiced baby, who may or may not have a surgically correctable hepatopathy. The approach has been systematically evaluated, but the etiology remains ambiguous. The study of families with recurrent biliary atresia has been undertaken at a molecular level. The primary interest with this disease is to identify the etiology and change the treatment from symptomatic to curative. The occurrence of this obstructive cholangio-hepatopathy in well-known genetic syndromes has suggested just coincidental finding, but the reality can be more intriguing because some of these diseases may have some interaction with the development of the intrahepatic biliary system. Several genes have been investigated thoroughly, including ADD3 and GPC1 shifting the interest from viruses to genetics. In this review, the intriguing complexities of this hepatobiliary disease are highlighted.
Collapse
Affiliation(s)
- Consolato M. Sergi
- Stollery Children’s Hospital, Laboratory Medicine and Pathology, University Alberta Hospital, University of Alberta, Edmonton, AB T6G 2B7, Canada
- Division of Anatomic Pathology, Children’s Hospital of Eastern Ontario, Ottawa, ON K1H 8L1, Canada
| | - Susan Gilmour
- Department of Pediatric Gastroenterology and Nutrition, University of Alberta, Edmonton, AB T6G 2B7, Canada;
| |
Collapse
|
|
6
|
Martins T, Meng Y, Korona B, Suckling R, Johnson S, Handford PA, Lea SM, Bray SJ. The conserved C2 phospholipid-binding domain in Delta contributes to robust Notch signalling. EMBO Rep 2021; 22:e52729. [PMID: 34347930 PMCID: PMC8490980 DOI: 10.15252/embr.202152729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/10/2021] [Accepted: 07/15/2021] [Indexed: 11/09/2022] Open
Abstract
Accurate Notch signalling is critical for development and homeostasis. Fine‐tuning of Notch–ligand interactions has substantial impact on signalling outputs. Recent structural studies have identified a conserved N‐terminal C2 domain in human Notch ligands which confers phospholipid binding in vitro. Here, we show that Drosophila ligands Delta and Serrate adopt the same C2 domain structure with analogous variations in the loop regions, including the so‐called β1‐2 loop that is involved in phospholipid binding. Mutations in the β1‐2 loop of the Delta C2 domain retain Notch binding but have impaired ability to interact with phospholipids in vitro. To investigate its role in vivo, we deleted five residues within the β1‐2 loop of endogenous Delta. Strikingly, this change compromises ligand function. The modified Delta enhances phenotypes produced by Delta loss‐of‐function alleles and suppresses that of Notch alleles. As the modified protein is present on the cell surface in normal amounts, these results argue that C2 domain phospholipid binding is necessary for robust signalling in vivo fine‐tuning the balance of trans and cis ligand–receptor interactions.
Collapse
Affiliation(s)
- Torcato Martins
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Yao Meng
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Richard Suckling
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Sarah J Bray
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| |
Collapse
|
|
7
|
Two Novel Mutations in the JAG1 Gene in Pediatric Patients with Alagille Syndrome: The First Case Series in Czech Republic. Diagnostics (Basel) 2021; 11:diagnostics11060983. [PMID: 34071626 PMCID: PMC8230072 DOI: 10.3390/diagnostics11060983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 11/30/2022] Open
Abstract
Background: Alagille syndrome (ALGS) is a highly variable multisystem disorder inherited in an autosomal dominant pattern with incomplete penetration. The disorder is caused by mutations in the JAG1 gene, only rarely in the NOTCH2 gene, which gives rise to malformations in multiple organs. Bile duct paucity is the main characteristic feature of the disease. Methods: Molecular-genetic examination of genes JAG1 and NOTCH2 in four probands of Czech origin who complied with the diagnostic criteria of ALGS was performed using targeted next-generation sequencing of genes JAG1 and NOTCH2. Segregation of variants in a family was assessed by Sanger sequencing of parental DNA. Results: Mutations in the JAG1 gene were confirmed in all four probands. We identified two novel mutations: c.3189dupG and c.1913delG. Only in one case, the identified JAG1 mutation was de novo. None of the parents carrying JAG1 pathogenic mutation was diagnosed with ALGS. Conclusion: Diagnosis of the ALGS is complicated due to the absence of clear genotype-phenotype correlations and the extreme phenotypic variability in the patients even within the same family. This fact is of particular importance in connection to genetic counselling and prenatal genetic testing.
Collapse
|
|
8
|
Coppens S, Barnard AM, Puusepp S, Pajusalu S, Õunap K, Vargas-Franco D, Bruels CC, Donkervoort S, Pais L, Chao KR, Goodrich JK, England EM, Weisburd B, Ganesh VS, Gudmundsson S, O'Donnell-Luria A, Nigul M, Ilves P, Mohassel P, Siddique T, Milone M, Nicolau S, Maroofian R, Houlden H, Hanna MG, Quinlivan R, Beiraghi Toosi M, Ghayoor Karimiani E, Costagliola S, Deconinck N, Kadhim H, Macke E, Lanpher BC, Klee EW, Łusakowska A, Kostera-Pruszczyk A, Hahn A, Schrank B, Nishino I, Ogasawara M, El Sherif R, Stojkovic T, Nelson I, Bonne G, Cohen E, Boland-Augé A, Deleuze JF, Meng Y, Töpf A, Vilain C, Pacak CA, Rivera-Zengotita ML, Bönnemann CG, Straub V, Handford PA, Draper I, Walter GA, Kang PB. A form of muscular dystrophy associated with pathogenic variants in JAG2. Am J Hum Genet 2021; 108:840-856. [PMID: 33861953 PMCID: PMC8206160 DOI: 10.1016/j.ajhg.2021.03.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/26/2021] [Indexed: 02/09/2023] Open
Abstract
JAG2 encodes the Notch ligand Jagged2. The conserved Notch signaling pathway contributes to the development and homeostasis of multiple tissues, including skeletal muscle. We studied an international cohort of 23 individuals with genetically unsolved muscular dystrophy from 13 unrelated families. Whole-exome sequencing identified rare homozygous or compound heterozygous JAG2 variants in all 13 families. The identified bi-allelic variants include 10 missense variants that disrupt highly conserved amino acids, a nonsense variant, two frameshift variants, an in-frame deletion, and a microdeletion encompassing JAG2. Onset of muscle weakness occurred from infancy to young adulthood. Serum creatine kinase (CK) levels were normal or mildly elevated. Muscle histology was primarily dystrophic. MRI of the lower extremities revealed a distinct, slightly asymmetric pattern of muscle involvement with cores of preserved and affected muscles in quadriceps and tibialis anterior, in some cases resembling patterns seen in POGLUT1-associated muscular dystrophy. Transcriptome analysis of muscle tissue from two participants suggested misregulation of genes involved in myogenesis, including PAX7. In complementary studies, Jag2 downregulation in murine myoblasts led to downregulation of multiple components of the Notch pathway, including Megf10. Investigations in Drosophila suggested an interaction between Serrate and Drpr, the fly orthologs of JAG1/JAG2 and MEGF10, respectively. In silico analysis predicted that many Jagged2 missense variants are associated with structural changes and protein misfolding. In summary, we describe a muscular dystrophy associated with pathogenic variants in JAG2 and evidence suggests a disease mechanism related to Notch pathway dysfunction.
Collapse
Affiliation(s)
- Sandra Coppens
- Center of Human Genetics, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Alison M Barnard
- Department of Physical Therapy, University of Florida College of Public Health and Health Professions, Gainesville, FL 32610, USA
| | - Sanna Puusepp
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu 50406, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu 50406, Estonia
| | - Sander Pajusalu
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu 50406, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu 50406, Estonia
| | - Katrin Õunap
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu 50406, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu 50406, Estonia
| | - Dorianmarie Vargas-Franco
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Christine C Bruels
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, NINDS, NIH, Bethesda, MD 20892, USA
| | - Lynn Pais
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Katherine R Chao
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Julia K Goodrich
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Eleina M England
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ben Weisburd
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Vijay S Ganesh
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Sanna Gudmundsson
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Anne O'Donnell-Luria
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mait Nigul
- Department of Radiology, Tartu University Hospital, Tartu 50406, Estonia
| | - Pilvi Ilves
- Institute of Clinical Medicine, University of Tartu, Tartu 50406, Estonia; Department of Radiology, Tartu University Hospital, Tartu 50406, Estonia
| | - Payam Mohassel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, NINDS, NIH, Bethesda, MD 20892, USA
| | - Teepu Siddique
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | | | - Stefan Nicolau
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Reza Maroofian
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London WC1E 6BT, UK
| | - Henry Houlden
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London WC1E 6BT, UK
| | - Michael G Hanna
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London WC1E 6BT, UK
| | - Ros Quinlivan
- Department of Neuromuscular Disorders, University College London Institute of Neurology, London WC1E 6BT, UK
| | - Mehran Beiraghi Toosi
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad 9176999311, Iran
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK; Innovative Medical Research Center, Mashhad Branch, Islamic Azad University, Mashhad 9187147578, Iran
| | - Sabine Costagliola
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moleculaire, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Nicolas Deconinck
- Centre de Référence Neuromusculaire and Paediatric Neurology Department, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, 1020 Brussels, Belgium
| | - Hazim Kadhim
- Neuropathology Unit, Department of Anatomic Pathology and Reference Center for Neuromuscular Pathology, Brugmann University Hospital-Children's Hospital, Université Libre de Bruxelles, 1020 Brussels, Belgium
| | - Erica Macke
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Brendan C Lanpher
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Anna Łusakowska
- Department of Neurology, Medical University of Warsaw, 02-091 Warsaw, Poland
| | | | - Andreas Hahn
- Department of Child Neurology, Justus-Liebig-University Giessen, 35390 Giessen, Germany
| | - Bertold Schrank
- Department of Neurology, DKD HELIOS Klinik Wiesbaden, 65191 Wiesbaden, Germany
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8551, Japan
| | - Masashi Ogasawara
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8551, Japan
| | - Rasha El Sherif
- Myo-Care Neuromuscular Center, Myo-Care National Foundation, Cairo 11865, Egypt
| | - Tanya Stojkovic
- APHP, Nord-Est/Ile-de-France Neuromuscular Reference Center, Myology Institute, Pitié-Salpêtrière Hospital, 75013 Paris, France; Sorbonne Université, INSERM, Center of Research in Myology, UMRS974, 75651 Paris Cedex 13, France
| | - Isabelle Nelson
- Sorbonne Université, INSERM, Center of Research in Myology, UMRS974, 75651 Paris Cedex 13, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Center of Research in Myology, UMRS974, 75651 Paris Cedex 13, France
| | - Enzo Cohen
- Sorbonne Université, INSERM, Center of Research in Myology, UMRS974, 75651 Paris Cedex 13, France
| | - Anne Boland-Augé
- Université Paris-Saclay, CEA, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Jean-François Deleuze
- Université Paris-Saclay, CEA, Centre National de Recherche en Génomique Humaine, 91057 Evry, France
| | - Yao Meng
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 3BZ, UK
| | - Catheline Vilain
- Center of Human Genetics, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Christina A Pacak
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610, USA; Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Neurology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | | | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, NINDS, NIH, Bethesda, MD 20892, USA
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 3BZ, UK
| | - Penny A Handford
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA 02111, USA
| | - Glenn A Walter
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610, USA; Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Neurology, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Institute for Translational Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| |
Collapse
|
|
9
|
Gürünlüoğlu S, Ceran C, Gürünlüoğlu K, Koçbiyik A, Gül M, Yıldız T, Bağ HG, Gül S, Taşçi A, Bayrakçi E, Akpinar N, Çin ES, Ateş H, Demircan M. Glial Cell Line-Derived Neurotrophic Factor, S-100 Protein and Synaptophysin Expression in Biliary Atresia Gallbladder Tissue. Pediatr Gastroenterol Hepatol Nutr 2021; 24:173-186. [PMID: 33833973 PMCID: PMC8007845 DOI: 10.5223/pghn.2021.24.2.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/09/2020] [Accepted: 10/20/2020] [Indexed: 11/14/2022] Open
Abstract
PURPOSE Biliary atresia (BA) is a disease that manifests as jaundice after birth and leads to progressive destruction of the ductal system in the liver. The aim of this study was to investigate histopathological changes and immunohistochemically examine the expression of glial cell line-derived neurotrophic factor (GDNF), synaptophysin, and S-100 protein in the gallbladder of BA patients. METHODS The study included a BA group of 29 patients and a control group of 41 children with cholecystectomy. Gallbladder tissue removed during surgery was obtained and examined immunohistochemically and histopathologically. Tissue samples of both groups were immunohistochemically assessed in terms of GDNF, S-100 protein, and synaptophysin expression. Expression was classified as present or absent. Inflammatory activity assessment with hematoxylin and eosin staining and fibrosis assessment with Masson's trichrome staining were performed for tissue sample sections of both groups. RESULTS Ganglion cells were not present in gallbladder tissue samples of the BA group. Immunohistochemically, GDNF, synaptophysin, and S-100 expression was not detected in the BA group. Histopathological examination revealed more frequent fibrosis and slightly higher inflammatory activity in the BA than in the control group. CONCLUSION We speculate that GDNF expression will no longer continue in this region, when the damage caused by inflammation of the extrahepatic bile ducts reaches a critical threshold. The study's findings may represent a missing link in the chain of events forming the etiology of BA and may be helpful in its diagnosis.
Collapse
Affiliation(s)
- Semra Gürünlüoğlu
- Department of Pathology Malatya Education and Research Hospital, Pathology Laboratory, Malatya, Turkey
| | - Canan Ceran
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Kubilay Gürünlüoğlu
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Alper Koçbiyik
- Department of Pathology, Istanbul Bakırköy Dr Sadi Konuk Education and Research Hospital, Pathology Laboratory, Istanbul, Turkey
| | - Mehmet Gül
- Department of Histology and Embryology, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Turan Yıldız
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Harika Gözükara Bağ
- Department of Biostatistics and Medical Informatics, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Semir Gül
- Department of Histology and Embryology, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Aytaç Taşçi
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Ercan Bayrakçi
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Necmettin Akpinar
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Ecem Serbest Çin
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Hasan Ateş
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| | - Mehmet Demircan
- Department of Pediatric Surgery, Faculty of Medicine, İnönü University, Malatya, Turkey
| |
Collapse
|
|
10
|
Whole exome sequencing analysis for mutations in isolated type III biliary atresia patients. Clin Exp Hepatol 2020; 6:347-353. [PMID: 33511283 PMCID: PMC7816631 DOI: 10.5114/ceh.2020.102156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/15/2020] [Indexed: 12/20/2022] Open
Abstract
Aim of the study Biliary atresia is an idiopathic, destructive disease that affects both extrahepatic and intrahepatic bile ducts with severe inflammation and manifests as progressive jaundice within the first few months of life. In this study, we aimed to investigate the significance of genetic mutations in the onset of biliary atresia disease. Material and methods With the approval of the ethics committee and parental consent, blood was taken from patients to obtain their DNA, and the study commenced. In this prospective study, we examined the DNA of 10 patients with no disease other than biliary atresia, and an exome sequence analysis was performed with the new-generation DNA sequencing method. The genetic structure of biliary atresia disease was examined by statistical analysis of the mutations, which were determined according to the reference DNA sequencing. Results In the exome sequence analysis, the number of mutations detected among the patients changed significantly; the lowest number was 12,591, and the maximum was 19,863. By examining these mutations, we identified the mutated genes that were common to all patients. Conclusions In this study, the highest mutation rates were detected in the PRIM2 and MAP2K3 genes. These genes have not previously been associated with biliary atresia.
Collapse
|
|
11
|
Association of common variation in ADD3 and GPC1 with biliary atresia susceptibility. Aging (Albany NY) 2020; 12:7163-7182. [PMID: 32315284 PMCID: PMC7202506 DOI: 10.18632/aging.103067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/29/2020] [Indexed: 02/06/2023]
Abstract
Biliary atresia (BA) is an idiopathic neonatal cholestatic disease. Recent genome-wide association study (GWAS) revealed that common variation of ADD3, GPC1, ARF6, and EFEMP1 gene was associated with BA susceptibility. We aimed to evaluate the association of these genes with BA in Chinese population. Twenty single nucleotide polymorphisms (SNPs) in these four genes were genotyped in 340 BA patients and 1,665 controls. Three SNPs in ADD3 were significantly associated with BA, and rs17095355 was the top SNP (PAllele = 3.23×10-6). Meta-analysis of published data and current data indicated that rs17095355 was associated with BA susceptibility in Asians and Caucasians. Three associated SNPs were expression quantitative trait loci (eQTL) for ADD3. Two GPC1 SNPs in high linkage disequilibrium (LD) showed nominal association with BA susceptibility (PAllele = 0.03 for rs6707262 and PAllele = 0.04 for rs6750380), and were eQTL of GPC1. Haplotype harboring these two SNPs almost reached the study-wide significance (P = 0.0035). No association for ARF6 and EFEMP1 was found with BA risk in the current population. Our study validated associations of ADD3 and GPC1 SNPs with BA risk in Chinese population and provided evidence of epistatic contributions of genetic factors to BA susceptibility.
Collapse
|
|
12
|
Vij M, Rela M. Biliary atresia: pathology, etiology and pathogenesis. Future Sci OA 2020; 6:FSO466. [PMID: 32518681 PMCID: PMC7273417 DOI: 10.2144/fsoa-2019-0153] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/30/2020] [Indexed: 02/06/2023] Open
Abstract
Biliary atresia is a progressive fibrosing obstructive cholangiopathy of the intrahepatic and extrahepatic biliary system, resulting in obstruction of bile flow and neonatal jaundice. Histopathological findings in liver biopsies include the expansion of the portal tracts, with edematous fibroplasia and bile ductular proliferation, with bile plugs in duct lumen. Lobular morphological features may include variable multinucleate giant cells, bilirubinostasis and hemopoiesis. The etiopathogenesis of biliary atresia is multifactorial and multiple pathomechanisms have been proposed. Experimental and clinical studies have suggested that viral infection initiates biliary epithelium destruction and release of antigens that trigger a Th1 immune response, which leads to further injury of the bile duct, resulting in inflammation and obstructive scarring of the biliary tree. It has also been postulated that biliary atresia is caused by a defect in the normal remodelling process. Genetic predisposition has also been proposed as a factor for the development of biliary atresia.
Collapse
Affiliation(s)
- Mukul Vij
- Senior Consultant Histopathologist, Department of Pathology, Dr Rela Institute & Medical Centre, Chennai, Tamil Nadu, India, 600044
| | - Mohamed Rela
- Institute of Liver Disease & Transplantation, Chairmen, Dr Rela Institute & Medical Centre, Chennai, Tamil Nadu, India, 600044
- Liver Transplant Unit, Kings College Hospital, London SE5 9RS, UK
| |
Collapse
|
|
13
|
Biliary Atresia as a Disease Starting In Utero: Implications for Treatment, Diagnosis, and Pathogenesis. J Pediatr Gastroenterol Nutr 2019; 69:396-403. [PMID: 31335837 PMCID: PMC6942669 DOI: 10.1097/mpg.0000000000002450] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Biliary atresia (BA) is the most common reason for pediatric liver transplant. BA's varied presentation, natural history, and treatment with the Kasai portoenterostomy have been well described; however, when BA starts relative to birth has not been clearly defined. In this review, we discuss laboratory, imaging, and clinical data which suggest that most if not all forms of BA may start before birth. This early onset has implications in terms of delivering treatments earlier and identifying possible factors underlying BA's etiology.
Collapse
|
|
14
|
Abstract
PURPOSE OF REVIEW Biliary atresia is a poorly understood deadly disease. Genetic predisposition factors are suspected albeit not firmly established. This review summarizes recent evidence of genetic alterations in biliary atresia. RECENT FINDINGS Whole-genome association studies in biliary atresia patients identified four distinct predisposition loci with four different genes potentially involved in the disease occurrence. Variations in these genes were searched for, but none were found in patients with biliary atresia suggesting complex mechanisms. SUMMARY Despite decades since its description and decades of intensive researches, cause of biliary atresia disease remains enigmatic. The inheritance of biliary atresia is not Mendelian. Genetic predisposition factor is one of the explored fields to explain biliary atresia pathogenicity. Biliary atresia has been associated with several inborn syndromes, chromosome anomalies, and gene polymorphisms in specific populations. Four predisposition loci encompassing genes relevant to the disease have been identified, but no pathogenic variations were found in biliary atresia patients. Few reported cases of isolated biliary atresia manifestation in the context of known genetic diseases suggest coincidental findings. Alternatives to classic genetic alterations are proposed to explain genetic predisposition in biliary atresia including noncoding and epigenetic factors. Biliary atresia is most likely related to complex traits making its genetic exploration challenging.
Collapse
|
|
15
|
Chen HL, Li HY, Wu JF, Wu SH, Chen HL, Yang YH, Hsu YH, Liou BY, Chang MH, Ni YH. Panel-Based Next-Generation Sequencing for the Diagnosis of Cholestatic Genetic Liver Diseases: Clinical Utility and Challenges. J Pediatr 2019; 205:153-159.e6. [PMID: 30366773 DOI: 10.1016/j.jpeds.2018.09.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/08/2018] [Accepted: 09/11/2018] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To test the application of a target enrichment next-generation sequencing (NGS) jaundice panel in genetic diagnosis of pediatric liver diseases. STUDY DESIGN We developed a capture-based target enrichment NGS jaundice panel containing 42 known disease-causing genes associated with jaundice or cholestasis and 10 pathway-related genes. During 2015-2017, 102 pediatric patients with various forms of cholestasis or idiopathic liver diseases were tested, including patients with initial diagnosis of cholestasis in infancy, progressive familial intrahepatic cholestasis, syndromic cholestasis, Wilson disease, and others. RESULTS Of the 102 patients, 137 mutations/variants in 44 different genes were identified in 84 patients. The genetic disease diagnosis rate was 33 of 102 (32.4%). A total of 79 of 102 (77.5%) of patients had at least 1 heterozygous genetic variation. Those with progressive intrahepatic cholestasis or syndromic cholestasis in infancy had a diagnostic rate of 62.5%. Disease-causing mutations, including ATP8B1, ABCB11, ABCB4, ABCC2, TJP2, NR1H4 (FXR), JAG1, AKR1D1, CYP7B1, PKHD1, ATP7B, and SLC25A13, were identified. Nine patients had unpredicted genetic diagnosis with atypical phenotype or novel mutations in the investigational genes. We propose an NGS diagnosis classification categorizing patients into high (n = 24), moderate (n = 9), or weak (n = 25) levels of genotype-phenotype correlations to facilitate patient management. CONCLUSIONS This panel enabled high-throughput detection of genetic variants and disease diagnosis in patients with a long list of candidate causative genes. A NGS report with diagnosis classification may aid clinicians in data interpretation and patient management.
Collapse
Affiliation(s)
- Huey-Ling Chen
- Department of Pediatrics, National Taiwan University College of Medicine and Children's Hospital, Taipei, Taiwan
| | - Huei-Ying Li
- Medical Microbiome Center, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jia-Feng Wu
- Department of Pediatrics, National Taiwan University College of Medicine and Children's Hospital, Taipei, Taiwan
| | - Shang-Hsin Wu
- Graduate Institution of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hui-Ling Chen
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Hsuan Yang
- Medical Microbiome Center, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yu-Hua Hsu
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
| | - Bang-Yu Liou
- Department of Pediatrics, National Taiwan University College of Medicine and Children's Hospital, Taipei, Taiwan
| | - Mei-Hwei Chang
- Department of Pediatrics, National Taiwan University College of Medicine and Children's Hospital, Taipei, Taiwan
| | - Yen-Hsuan Ni
- Department of Pediatrics, National Taiwan University College of Medicine and Children's Hospital, Taipei, Taiwan; Medical Microbiome Center, National Taiwan University College of Medicine, Taipei, Taiwan; Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan.
| |
Collapse
|
|
16
|
Ghazy RM, Adawy NM, Khedr MA, Tahoun MM. Biliary atresia recent insight. EGYPTIAN PEDIATRIC ASSOCIATION GAZETTE 2018. [DOI: 10.1016/j.epag.2017.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
|
|
17
|
Sangkhathat S, Laochareonsuk W, Maneechay W, Kayasut K, Chiengkriwate P. Variants Associated with Infantile Cholestatic Syndromes Detected in Extrahepatic Biliary Atresia by Whole Exome Studies: A 20-Case Series from Thailand. J Pediatr Genet 2018; 7:67-73. [PMID: 29707407 DOI: 10.1055/s-0038-1632395] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 01/14/2018] [Indexed: 02/08/2023]
Abstract
Biliary atresia (BA) is the most severe form of obstructive cholangiopathy occurring in infants. Definitive diagnosis of BA usually relies on operative findings together with supporting pathological patterns found in the extrahepatic bile duct. In infancy, overlapping clinical patterns of cholestasis can be found in other diseases including biliary hypoplasia and progressive familial intrahepatic cholestasis. In addition, BA has been reported as a phenotype in some rare genetic syndromes. Unlike BA, other cholangiopathic phenotypes have their own established genetic markers. In this study, we used these markers to look for other cholestasis entities in cases diagnosed with BA. DNA from 20 cases of BA, diagnosed by operative findings and histopathology, were subjected to a study of 19 genes associated with infantile cholestasis syndromes, using whole exome sequencing. Variant selection focused on those with allele frequencies in dbSNP150 of less than 0.01. All selected variants were verified by polymerase chain reaction-direct sequencing. Of the 20 cases studied, 13 rare variants were detected in 9 genes: 4 in JAG1 (Alagille syndrome), 2 in MYO5B (progressive familial intrahepatic cholestasis [PFIC] type 6), and one each in ABCC2 (Dubin-Johnson syndrome), ABCB11 (PFIC type 2), UG1A1 (Crigler-Najjar syndrome), MLL2 (Kabuki syndrome), RFX6 (Mitchell-Riley syndrome), ERCC4 (Fanconi anemia), and KCNH1 (Zimmermann-Laband syndrome). Genetic lesions associated with various cholestatic syndromes detected in cases diagnosed with BA raised the hypothesis that severe inflammatory cholangiopathy in BA may not be a distinct disease entity, but a shared pathology among several infantile cholestatic syndromes.
Collapse
Affiliation(s)
- Surasak Sangkhathat
- Pediatric Surgery Unit, Department of Surgery, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Wison Laochareonsuk
- Pediatric Surgery Unit, Department of Surgery, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Wanwisa Maneechay
- Central Research Laboratory, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Kanita Kayasut
- Anatomical Pathology Unit, Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Piyawan Chiengkriwate
- Pediatric Surgery Unit, Department of Surgery, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| |
Collapse
|
|
18
|
Ohashi K, Togawa T, Sugiura T, Ito K, Endo T, Aoyama K, Negishi Y, Kudo T, Ito R, Saitoh S. Combined genetic analyses can achieve efficient diagnostic yields for subjects with Alagille syndrome and incomplete Alagille syndrome. Acta Paediatr 2017; 106:1817-1824. [PMID: 28695677 DOI: 10.1111/apa.13981] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/01/2017] [Accepted: 07/05/2017] [Indexed: 12/15/2022]
Abstract
AIM We evaluated combined genetic analyses with targeted next-generation sequencing (NGS), multiplex ligation probe amplification (MLPA) of Jagged1 (JAG1) genes and microarray comparative genomic hybridisation (CGH) in subjects with Alagille syndrome, incomplete clinical features of Alagille syndrome and biliary atresia. METHODS Subjects recruited from April 2013 to December 2015 underwent a targeted NGS analysis, including JAG1 and Notch homolog 2 (NOTCH2). If no mutations were detected in JAG1 or NOTCH2, or if copy number variations were suggested by the NGS analysis, we performed an MLPA analysis of JAG1. We also performed a microarray CGH analysis with whole-exon deletion detected by the MLPA analysis. RESULTS We analysed 30 subjects with Alagille syndrome, nine with incomplete Alagille syndrome and 17 with biliary atresia and detected pathogenic mutations in JAG1 or NOTCH2 in 24/30 subjects with Alagille syndrome and in 4/9 subjects with incomplete Alagille syndrome. No pathogenic mutations were detected in subjects with biliary atresia. The frequency of JAG1 mutations was as follows: single nucleotide variants (51.9%), small insertion or deletion (29.6%) and gross deletion (18.5%). CONCLUSION Combined genetic analyses achieved efficient diagnostic yields for subjects with Alagille syndrome and incomplete Alagille syndrome.
Collapse
Affiliation(s)
- Kei Ohashi
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Takao Togawa
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Tokio Sugiura
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Koichi Ito
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Takeshi Endo
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Kohei Aoyama
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Yutaka Negishi
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| | - Toyoichiro Kudo
- Department of Hepatology; National Medical Center for Children and Mothers; National Center for Child Health and Development; Tokyo Japan
| | - Reiko Ito
- Department of Hepatology; National Medical Center for Children and Mothers; National Center for Child Health and Development; Tokyo Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology; Graduate School of Medical Sciences; Nagoya City University; Nagoya Japan
| |
Collapse
|
|
19
|
Suckling RJ, Korona B, Whiteman P, Chillakuri C, Holt L, Handford PA, Lea SM. Structural and functional dissection of the interplay between lipid and Notch binding by human Notch ligands. EMBO J 2017; 36:2204-2215. [PMID: 28572448 PMCID: PMC5538765 DOI: 10.15252/embj.201796632] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/06/2017] [Accepted: 04/07/2017] [Indexed: 12/30/2022] Open
Abstract
Recent data have expanded our understanding of Notch signalling by identifying a C2 domain at the N-terminus of Notch ligands, which has both lipid- and receptor-binding properties. We present novel structures of human ligands Jagged2 and Delta-like4 and human Notch2, together with functional assays, which suggest that ligand-mediated coupling of membrane recognition and Notch binding is likely to be critical in establishing the optimal context for Notch signalling. Comparisons between the Jagged and Delta family show a huge diversity in the structures of the loops at the apex of the C2 domain implicated in membrane recognition and Jagged1 missense mutations, which affect these loops and are associated with extrahepatic biliary atresia, lead to a loss of membrane recognition, but do not alter Notch binding. Taken together, these data suggest that C2 domain binding to membranes is an important element in tuning ligand-dependent Notch signalling in different physiological contexts.
Collapse
Affiliation(s)
| | | | - Pat Whiteman
- Department of BiochemistryUniversity of OxfordOxfordUK
| | | | - Laurie Holt
- Department of BiochemistryUniversity of OxfordOxfordUK
| | | | - Susan M Lea
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| |
Collapse
|
|
20
|
Zagory JA, Dietz W, Park A, Fenlon M, Xu J, Utley S, Mavila N, Wang KS. Notch signaling promotes ductular reactions in biliary atresia. J Surg Res 2017; 215:250-256. [DOI: 10.1016/j.jss.2017.03.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/13/2017] [Accepted: 03/29/2017] [Indexed: 12/29/2022]
|
|
21
|
Higashiyama H, Ozawa A, Sumitomo H, Uemura M, Fujino K, Igarashi H, Imaimatsu K, Tsunekawa N, Hirate Y, Kurohmaru M, Saijoh Y, Kanai-Azuma M, Kanai Y. Embryonic cholecystitis and defective gallbladder contraction in the Sox17-haploinsufficient mouse model of biliary atresia. Development 2017; 144:1906-1917. [PMID: 28432216 DOI: 10.1242/dev.147512] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 04/12/2017] [Indexed: 12/15/2022]
Abstract
The gallbladder excretes cytotoxic bile acids into the duodenum through the cystic duct and common bile duct system. Sox17 haploinsufficiency causes biliary atresia-like phenotypes and hepatitis in late organogenesis mouse embryos, but the molecular and cellular mechanisms underlying this remain unclear. In this study, transcriptomic analyses revealed the early onset of cholecystitis in Sox17+/- embryos, together with the appearance of ectopic cystic duct-like epithelia in their gallbladders. The embryonic hepatitis showed positive correlations with the severity of cholecystitis in individual Sox17+/- embryos. Embryonic hepatitis could be induced by conditional deletion of Sox17 in the primordial gallbladder epithelia but not in fetal liver hepatoblasts. The Sox17+/- gallbladder also showed a drastic reduction in sonic hedgehog expression, leading to aberrant smooth muscle formation and defective contraction of the fetal gallbladder. The defective gallbladder contraction positively correlated with the severity of embryonic hepatitis in Sox17+/- embryos, suggesting a potential contribution of embryonic cholecystitis and fetal gallbladder contraction in the early pathogenesis of congenital biliary atresia.
Collapse
Affiliation(s)
- Hiroki Higashiyama
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Aisa Ozawa
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hiroyuki Sumitomo
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Mami Uemura
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.,Center for Experimental Animals, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Ko Fujino
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hitomi Igarashi
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kenya Imaimatsu
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Naoki Tsunekawa
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yoshikazu Hirate
- Center for Experimental Animals, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Masamichi Kurohmaru
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yukio Saijoh
- Department of Neurobiology and Anatomy, The University of Utah, Salt Lake City, UT 84132-3401, USA
| | - Masami Kanai-Azuma
- Center for Experimental Animals, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Yoshiakira Kanai
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| |
Collapse
|
|
22
|
Cheng G, Chung PHY, Chan EKW, So MT, Sham PC, Cherny SS, Tam PKH, Garcia-Barceló MM. Patient complexity and genotype-phenotype correlations in biliary atresia: a cross-sectional analysis. BMC Med Genomics 2017; 10:22. [PMID: 28416017 PMCID: PMC5392958 DOI: 10.1186/s12920-017-0259-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 04/05/2017] [Indexed: 12/11/2022] Open
Abstract
Background Biliary Atresia (BA) is rare and genetically complex, and the pathogenesis is elusive. The disease course is variable and can represent heterogeneity, which hinders effective disease management. Deciphering the BA phenotypic variance is a priority in clinics and can be achieved by the integrative analysis of genotype and phenotype. We aim to explore the BA phenotypic features and to delineate the source of its variance. Methods The study is a cross-sectional observational study collating with case/control association analysis. One-hundred-and-eighty-one type III non-syndromic BA patients and 431 controls were included for case–control association tests, including 89 patients (47.19% males, born June 15th, 1981 to September 17th, 2007) have detailed clinical records with follow-up of the disease course (median ~17.2 years). BA-association genes from the genome-wide gene-based association test on common genetic variants (CV) and rare copy-number-variants (CNVs) from the genome-wide survey, the later comprise only CNVs > 100 kb and found in the BA patients but not in the local population (N = 1,381) or the database (N = 11,943). Hereby comorbidity is defined as a chronic disease that affects the BA patients but has no known relationship with BA or with the BA treatment. We examined genotype-phenotype correlations of CNVs, connectivity of these novel variants with BA-associated CVs, and their role in the BA candidate gene network. Results Of the 89 patients, 41.57% have comorbidities, including autoimmune-allergic disorders (22.47%). They carried 29 BA-private CNVs, including 3 CNVs underpinning the carriers’ immunity comorbidity and one JAG1 micro-deletion. The BA-CNV-intersected genes (N = 102) and the CV-tagged genes (N = 103) were both enriched with immune-inflammatory pathway genes (FDR q < 0.20), and the two gene sets were interconnected (permutation p = 0.039). The molecular network representing CVs and rare-CNV association genes fit into a core/periphery structure, the immune genes and their related modules are found at the coherence core of all connections, suggesting its dominant role in the BA pathogenesis pathway. Conclusions The study highlights a patient-complexity phenomenon as a novel BA phenotypic feature, which is underpinned by rare-CNVs that biologically converge with CVs into the immune-inflammatory pathway and drives the BA occurrence and the likely BA association with immune diseases in clinics. Electronic supplementary material The online version of this article (doi:10.1186/s12920-017-0259-0) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Guo Cheng
- Department of Surgery, 1/F Hong Kong Jockey Club Building for Interdisciplinary Research, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Patrick Ho-Yu Chung
- Department of Surgery, 1/F Hong Kong Jockey Club Building for Interdisciplinary Research, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Edwin Kin-Wai Chan
- Department of Surgery, the Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Man-Ting So
- Department of Surgery, 1/F Hong Kong Jockey Club Building for Interdisciplinary Research, 5 Sassoon Road, Pokfulam, Hong Kong
| | - Pak-Chung Sham
- Department of Psychiatry, The University of Hong Kong, Hong Kong, SAR, China.,Center for Genomic Sciences, Hong Kong, SAR, China.,Centre for Reproduction, Development, Growth of the Li Ka Shing Faculty of Medicine, Hong Kong, SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Stacey S Cherny
- Department of Psychiatry, The University of Hong Kong, Hong Kong, SAR, China.,Center for Genomic Sciences, Hong Kong, SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Paul Kwong-Hang Tam
- Department of Surgery, 1/F Hong Kong Jockey Club Building for Interdisciplinary Research, 5 Sassoon Road, Pokfulam, Hong Kong.,Centre for Reproduction, Development, Growth of the Li Ka Shing Faculty of Medicine, Hong Kong, SAR, China
| | - Maria-Mercè Garcia-Barceló
- Department of Surgery, 1/F Hong Kong Jockey Club Building for Interdisciplinary Research, 5 Sassoon Road, Pokfulam, Hong Kong. .,Center for Genomic Sciences, Hong Kong, SAR, China. .,Centre for Reproduction, Development, Growth of the Li Ka Shing Faculty of Medicine, Hong Kong, SAR, China.
| |
Collapse
|
|
23
|
Biliary atresia: Clinical advances and perspectives. Clin Res Hepatol Gastroenterol 2016; 40:281-287. [PMID: 26775892 DOI: 10.1016/j.clinre.2015.11.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 11/03/2015] [Accepted: 11/16/2015] [Indexed: 02/04/2023]
Abstract
Biliary atresia (BA) is a rare and severe inflammatory and obliterative cholangiopathy that affects both extra- and intrahepatic bile ducts. BA symptoms occur shortly after birth with jaundice, pale stools and dark urines. The prognosis of BA has dramatically changed in the last decades: before the Kasai operation most BA patients died, while nowadays with the sequential treatment with Kasai operation±liver transplantation BA patient survival is close to 90%. Early diagnosis is very important since the chances of success of the Kasai procedure decrease with time. The causes of BA remain actually unknown but several mechanisms including genetic and immune dysregulation may probably lead to the obliterative cholangiopathy. Current research focuses on the identification of blood or liver factors linked to the pathogenesis of BA that could become therapeutic targets and avoid the need for liver transplantation. No similar disease leading to total obstruction of the biliary tree exists in older children or adults. But understanding the physiopathology of BA may highlight the mechanisms of other destructive cholangiopathies, such as sclerosing cholangitis.
Collapse
|
|
24
|
Dědič T, Jirsa M, Keil R, Rygl M, Šnajdauf J, Kotalová R. Alagille Syndrome Mimicking Biliary Atresia in Early Infancy. PLoS One 2015; 10:e0143939. [PMID: 26618708 PMCID: PMC4664419 DOI: 10.1371/journal.pone.0143939] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 11/11/2015] [Indexed: 11/18/2022] Open
Abstract
Alagille syndrome may mimic biliary atresia in early infancy. Since mutations in JAG1 typical for Alagille syndrome type 1 have also been found in biliary atresia, we aimed to identify JAG1 mutations in newborns with proven biliary atresia (n = 72). Five biliary atresia patients with cholestasis, one additional characteristic feature of Alagille syndrome and ambiguous liver histology were single heterozygotes for nonsense or frameshift mutations in JAG1. No mutations were found in the remaining 67 patients. All "biliary atresia" carriers of JAG1 null mutations developed typical Alagille syndrome at the age of three years. Our data do not support association of biliary atresia with JAG1 mutations, at least in Czech patients. Rapid testing for JAG1 mutations could prevent misdiagnosis of Alagille syndrome in early infancy and improve their outcome.
Collapse
Affiliation(s)
- Tomáš Dědič
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic
| | - Milan Jirsa
- Laboratory of Experimental Hepatology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Radan Keil
- Department of Internal Medicine, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic
| | - Michal Rygl
- Department of Paediatric Surgery, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic
| | - Jiri Šnajdauf
- Department of Paediatric Surgery, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic
| | - Radana Kotalová
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic
- * E-mail:
| |
Collapse
|
|
25
|
Cho JM, Oh SH, Kim HJ, Kim JS, Kim KM, Kim GH, Yu E, Lee BH, Yoo HW. Clinical features, outcomes, and genetic analysis in Korean children with Alagille syndrome. Pediatr Int 2015; 57:552-7. [PMID: 25676721 DOI: 10.1111/ped.12602] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 12/26/2014] [Accepted: 01/28/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND Alagille syndrome (AGS) is a multisystem autosomal dominant disorder that affects the liver, heart, eyes, face, bone, and other organs. AGS is caused by mutations in one of two genes, JAG1 or NOTCH2. We evaluated clinical features, outcomes, and the presence of JAG1 and NOTCH2 mutations in Korean children with AGS. METHODS Between January 1997 and December 2013, 19 children were diagnosed with AGS at Asan Medical Center, Seoul, Korea. Their clinical features, outcomes, and JAG1 and NOTCH2 mutation status were retrospectively analyzed. RESULTS The prevalence of clinical features in the 19 patients was as follows: dysmorphic facial features, 100% (n = 19); liver symptoms, 89% (n = 17); cardiac symptoms, 95% (n = 18); ophthalmologic symptoms, 67% (n = 10); skeletal deformities, 47% (n = 9); and renal symptoms, 21% (n = 4). JAG1 mutations were identified in 14 patients. The 13 different JAG1 mutations, seven of which were novel, included four deletions, three insertions, two missense mutations, three nonsense mutations, and one indel mutation. No NOTCH2 mutations were found. Two patients who received liver transplantation due to liver failure were still alive. Two patients died of comorbidities related to AGS: one of cardiac failure and one of hepatic failure. CONCLUSION This study describes the clinical characteristics of 19 Korean AGS patients with seven novel JAG1 mutations. Neonatal cholestatic jaundice was the most common initial presenting symptom; thus the presence of neonatal cholestasis warrants screening for syndromic features of AGS. Complex heart anomalies and progressive liver dysfunction resulted in significant morbidity and mortality in AGS.
Collapse
Affiliation(s)
- Jin Min Cho
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Seak Hee Oh
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyun Jin Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Joon Sung Kim
- Department of Pediatrics, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
| | - Kyung Mo Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Gu-Hwan Kim
- Genome Research Center for Genetic Disorders, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Eunsil Yu
- Pathology, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Beom Hee Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea.,Genome Research Center for Genetic Disorders, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Han-Wook Yoo
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea.,Genome Research Center for Genetic Disorders, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| |
Collapse
|
|
26
|
Abstract
Biliary atresia is a severe cholangiopathy of early infancy that destroys extrahepatic bile ducts and disrupts bile flow. With a poorly defined disease pathogenesis, treatment consists of the surgical removal of duct remnants followed by hepatoportoenterostomy. Although this approach can improve the short-term outcome, the liver disease progresses to end-stage cirrhosis in most children. Further improvement in outcome will require a greater understanding of the mechanisms of biliary injury and fibrosis. Here, we review progress in the field, which has been fuelled by collaborative studies in larger patient cohorts and the development of cell culture and animal model systems to directly test hypotheses. Advances include the identification of phenotypic subgroups and stages of disease based on clinical, pathological and molecular features. Stronger evidence exists for viruses, toxins and gene sequence variations in the aetiology of biliary atresia, triggering a proinflammatory response that injures the duct epithelium and produces a rapidly progressive cholangiopathy. The immune response also activates the expression of type 2 cytokines that promote epithelial cell proliferation and extracellular matrix production by nonparenchymal cells. These advances provide insight into phenotype variability and might be relevant to the design of personalized trials to block progression of liver disease.
Collapse
|
|
27
|
Kotalova R, Dusatkova P, Cinek O, Dusatkova L, Dedic T, Seeman T, Lebl J, Pruhova S. Hepatic phenotypes of HNF1B gene mutations: A case of neonatal cholestasis requiring portoenterostomy and literature review. World J Gastroenterol 2015; 21:2550-2557. [PMID: 25741167 PMCID: PMC4342936 DOI: 10.3748/wjg.v21.i8.2550] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 08/28/2014] [Accepted: 12/01/2014] [Indexed: 02/06/2023] Open
Abstract
Hepatocyte nuclear factor 1-β (HNF1B) defects cause renal cysts and diabetes syndrome (RCAD), or HNF1B-maturity-onset diabetes of the young. However, the hepatic phenotype of HNF1B variants is not well studied. We present a female neonate born small for her gestational age [birth weight 2360 g; -2.02 standard deviations (SD) and birth length 45 cm; -2.40 SD at the 38th gestational week]. She developed neonatal cholestasis due to biliary atresia and required surgical intervention (portoenterostomy) when 32-d old. Following the operation, icterus resolved, but laboratory signs of liver dysfunction persisted. She had hyperechogenic kidneys prenatally with bilateral renal cysts and pancreatic hypoplasia postnatally that led to the diagnosis of an HNF1B deletion. This represents the most severe hepatic phenotype of an HNF1B variant recognized thus far. A review of 12 published cases with hepatic phenotypes of HNF1B defects allowed us to distinguish three severity levels, ranging from neonatal cholestasis through adult-onset cholestasis to non-cholestatic liver impairment, all of these are associated with congenital renal cysts and mostly with diabetes later in life. We conclude that to detect HNF1B variants, neonates with cholestasis should be checked for the presence of renal cysts, with special focus on those who are born small for their gestational age. Additionally, patients with diabetes and renal cysts at any age who develop cholestasis and/or exocrine pancreatic insufficiency should be tested for HNF1B variants as the true etiological factor of all disease components. Further observations are needed to confirm the potential reversibility of cholestasis in infancy in HNF1B mutation/deletion carriers.
Collapse
MESH Headings
- Biliary Atresia/complications
- Biliary Atresia/diagnosis
- Biliary Atresia/genetics
- Birth Weight
- Central Nervous System Diseases/complications
- Central Nervous System Diseases/diagnosis
- Central Nervous System Diseases/genetics
- Cholangiopancreatography, Magnetic Resonance
- Cholestasis/diagnosis
- Cholestasis/genetics
- Cholestasis/surgery
- DNA Mutational Analysis
- Dental Enamel/abnormalities
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/diagnosis
- Diabetes Mellitus, Type 2/genetics
- Female
- Genetic Predisposition to Disease
- Hepatocyte Nuclear Factor 1-beta/genetics
- Humans
- Infant
- Infant, Newborn
- Infant, Small for Gestational Age
- Kidney Diseases, Cystic/complications
- Kidney Diseases, Cystic/diagnosis
- Kidney Diseases, Cystic/genetics
- Mutation
- Phenotype
- Portoenterostomy, Hepatic
- Treatment Outcome
Collapse
|
|
28
|
Arva NC, Russo PA, Erlichman J, Hancock WW, Haber BA, Bhatti TR. The inflammatory phenotype of the fibrous plate is distinct from the liver and correlates with clinical outcome in biliary atresia. Pathol Res Pract 2015; 211:252-60. [PMID: 25624184 DOI: 10.1016/j.prp.2014.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/18/2014] [Accepted: 12/05/2014] [Indexed: 01/24/2023]
Abstract
Biliary atresia is an inflammatory cholangiopathy of still undetermined etiology. Correlations between histologic findings and clinical outcome in this disease have largely been based on evaluation of liver parenchyma. This study aimed to characterize the pattern of inflammation within the biliary remnant and identify associations between the type and degree of inflammation and clinical outcome as reflected by the transplant-free interval. The inflammation within the fibrous plates and livers of 41 patients with biliary atresia was characterized using immunohistochemical markers and the cell populations were digitally quantified. The type and quantity of cells within the infiltrate were then correlated with length of time from Kasai portoenterostomy until transplant. Histologic and immunohistochemical features of the biliary remnant allowed stratification of patients into "inflammatory plate" and "fibrotic plate" groups. Overall there was no significant difference in transplant-free interval between the two cohorts; however, there was a trend towards a longer time to transplant among patients in the "fibrotic plate" group. In addition, the composition of the inflammatory infiltrate in the fibrous plate was distinctly different from that present in the liver and only the characteristics of the inflammation in the fibrous plate, in particular the number of Foxp3+ T regulatory lymphocytes correlated with clinical outcome. The results of this study support the view of the extra-hepatic biliary tree as the primary site of injury in BA with the changes seen in the liver as secondary manifestations of outflow obstruction. The association between specific inflammatory cell subtypes within the fibrous plate and the length of transplant-free interval also supports the role of the immune system in the initial process of bile duct damage in biliary atresia.
Collapse
Affiliation(s)
- Nicoleta C Arva
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Pierre A Russo
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, USA
| | - Jessi Erlichman
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Wayne W Hancock
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, USA
| | | | - Tricia R Bhatti
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
| |
Collapse
|
|
29
|
Goodhue CJ, Wang KS. Persistent hyperbilirubinemia in a newborn. J Pediatr Health Care 2014; 28:172-6. [PMID: 23602430 DOI: 10.1016/j.pedhc.2012.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/02/2012] [Accepted: 12/26/2012] [Indexed: 10/26/2022]
|
|
30
|
Etiology of biliary atresia as a developmental anomaly: recent advances. JOURNAL OF HEPATO-BILIARY-PANCREATIC SCIENCES 2014; 20:459-64. [PMID: 23567964 DOI: 10.1007/s00534-013-0604-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Biliary atresia (BA) is a progressive fibro-obliterative cholangiopathy affecting the extra- and intrahepatic biliary tree to various degrees and resulting in obstructive bile flow, cholestasis and icterus in neonates. It is the most common cause of pediatric liver transplantation. The etiology of BA is still unclear, although there is some evidence pointing to viral, toxic, and multiple genetic factors. For new therapeutic options other than liver transplantation to be developed, a greater understanding of the pathogenesis of BA is indispensable. The fact that the pathology of BA develops during a period of biliary growth and remodeling suggests an involvement of developmental anomalies. Recent studies indicate an association of the etiology of BA with some genetic factors such as laterality genes, epigenetic regulation and/or microRNA function. In this paper, we present an overview of recent advances in the understanding of the disease focusing on bile duct developmental anomaly.
Collapse
|
|
31
|
Schwarz KB, Haber BH, Rosenthal P, Mack CL, Moore J, Bove KE, Bezerra JA, Karpen SJ, Kerkar N, Shneider BL, Turmelle YP, Whitington PF, Molleston JP, Murray KF, Ng VL, Romero R, Wang KS, Sokol RJ, Magee JC. Extrahepatic anomalies in infants with biliary atresia: results of a large prospective North American multicenter study. Hepatology 2013; 58:1724-31. [PMID: 23703680 PMCID: PMC3844083 DOI: 10.1002/hep.26512] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 04/28/2013] [Accepted: 05/02/2013] [Indexed: 12/25/2022]
Abstract
UNLABELLED The etiology of biliary atresia (BA) is unknown. Given that patterns of anomalies might provide etiopathogenetic clues, we used data from the North American Childhood Liver Disease Research and Education Network to analyze patterns of anomalies in infants with BA. In all, 289 infants who were enrolled in the prospective database prior to surgery at any of 15 participating centers were evaluated. Group 1 was nonsyndromic, isolated BA (without major malformations) (n = 242, 84%), Group 2 was BA and at least one malformation considered major as defined by the National Birth Defects Prevention Study but without laterality defects (n = 17, 6%). Group 3 was syndromic, with laterality defects (n = 30, 10%). In the population as a whole, anomalies (either major or minor) were most prevalent in the cardiovascular (16%) and gastrointestinal (14%) systems. Group 3 patients accounted for the majority of subjects with cardiac, gastrointestinal, and splenic anomalies. Group 2 subjects also frequently displayed cardiovascular (71%) and gastrointestinal (24%) anomalies; interestingly, this group had genitourinary anomalies more frequently (47%) compared to Group 3 subjects (10%). CONCLUSION This study identified a group of BA (Group 2) that differed from the classical syndromic and nonsyndromic groups and that was defined by multiple malformations without laterality defects. Careful phenotyping of the patterns of anomalies may be critical to the interpretation of both genetic and environmental risk factors associated with BA, allowing new insight into pathogenesis and/or outcome.
Collapse
Affiliation(s)
| | | | | | - Cara L Mack
- University of Colorado School of Medicine, Aurora, CO.
| | - Jeffrey Moore
- University of Michigan School of Public Health, Ann Arbor, MI.
| | - Kevin E Bove
- Cincinnati Children’s Hospital Medical Center, Cincinnati, OH. ,
| | - Jorge A Bezerra
- Cincinnati Children’s Hospital Medical Center, Cincinnati, OH. ,
| | | | | | | | | | | | - Jean P Molleston
- Indiana University, Riley Hospital for Children, Indianapolis, IN.
| | - Karen F Murray
- Seattle Children’s and University of Washington, Seattle, WA.
| | - Vicky L Ng
- The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
| | | | - Kasper S Wang
- Children’s Hospital Los Angeles, Keck School of Medicine University of Southern California, Los Angeles, CA.
| | | | - John C Magee
- University of Michigan Medical School, Ann Arbor, MI.
| |
Collapse
|
|
32
|
Uemura M, Ozawa A, Nagata T, Kurasawa K, Tsunekawa N, Nobuhisa I, Taga T, Hara K, Kudo A, Kawakami H, Saijoh Y, Kurohmaru M, Kanai-Azuma M, Kanai Y. Sox17 haploinsufficiency results in perinatal biliary atresia and hepatitis in C57BL/6 background mice. Development 2013; 140:639-48. [PMID: 23293295 DOI: 10.1242/dev.086702] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Congenital biliary atresia is an incurable disease of newborn infants, of unknown genetic causes, that results in congenital deformation of the gallbladder and biliary duct system. Here, we show that during mouse organogenesis, insufficient SOX17 expression in the gallbladder and bile duct epithelia results in congenital biliary atresia and subsequent acute 'embryonic hepatitis', leading to perinatal death in ~95% of the Sox17 heterozygote neonates in C57BL/6 (B6) background mice. During gallbladder and bile duct development, Sox17 was expressed at the distal edge of the gallbladder primordium. In the Sox17(+/-) B6 embryos, gallbladder epithelia were hypoplastic, and some were detached from the luminal wall, leading to bile duct stenosis or atresia. The shredding of the gallbladder epithelia is probably caused by cell-autonomous defects in proliferation and maintenance of the Sox17(+/-) gallbladder/bile duct epithelia. Our results suggest that Sox17 plays a dosage-dependent function in the morphogenesis and maturation of gallbladder and bile duct epithelia during the late-organogenic stages, highlighting a novel entry point to the understanding of the etiology and pathogenesis of human congenital biliary atresia.
Collapse
Affiliation(s)
- Mami Uemura
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
|
33
|
Moreira RK, Cabral R, Cowles RA, Lobritto SJ. Biliary atresia: a multidisciplinary approach to diagnosis and management. Arch Pathol Lab Med 2012; 136:746-60. [PMID: 22742548 DOI: 10.5858/arpa.2011-0623-ra] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Biliary atresia is an inflammatory cholangiopathy of infancy that results in progressive fibrosis and obliteration of bile ducts and represents the main indication for liver transplant in young children. In spite of extensive investigation, its etiology has remained poorly understood. Timely surgical intervention (Kasai procedure) may result in significant benefit to these patients and represents the final goal of an accurate diagnostic evaluation. OBJECTIVE To present an overview of biliary atresia, including clinical and surgical approaches to this disease, with emphasis on the histopathologic evaluation. DATA SOURCES Review of relevant literature indexed in PubMed (US National Library of Medicine). CONCLUSION A well-coordinated multidisciplinary approach is required in the assessment of suspected cases of biliary atresia. Pathologic examination of biopsy specimens is an integral part of the diagnostic algorithm and, therefore, plays a pivotal role in the diagnostic evaluation of this disease.
Collapse
Affiliation(s)
- Roger Klein Moreira
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
| | | | | | | |
Collapse
|
|
34
|
Rance E, Tanner JE, Alfieri C. Inhibition of IκB kinase by thalidomide increases hepatitis C virus RNA replication. J Viral Hepat 2012; 19:e73-80. [PMID: 22239529 DOI: 10.1111/j.1365-2893.2011.01505.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hepatic fibrosis is an integral element in the progression of chronic liver disease. Elevated hepatic interleukin (IL)-8 is an important contributor to fibrosis in patients chronically infected with the hepatitis C virus (HCV). Thalidomide has been used to reduce liver inflammation and fibrosis in HCV-infected patients, but its impact on HCV replication remains unclear. This study examined the effect of thalidomide on HCV replication in vitro. Results revealed that while thalidomide reduced IL-8 and nuclear factor kappa B (NF-κB) activity by 95% and 46% in Huh-7 cells, increasing concentrations of thalidomide correlated with a linear rise in HCV replication (17-fold at 200 μm). The NF-κB inhibitors, wedelolactone and NF-κB activation inhibitor-1, which mimic the actions of thalidomide by preventing phosphorylation and activation of IκB kinase (IKK) and hence block NF-κB activity, increased HCV RNA by 18- and 19-fold, respectively. During in vitro HCV replication in Huh-7 cells, we observed a 30% increase in IKKα protein and 55% decrease in NF-κB(p65)/RelA protein relative to cellular β-actin. Ectopic expression of IKKα to enhance the inactive form of IKK in cells undergoing virus replication led to a 13-fold increase in HCV RNA. Conversely, enhanced expression of NF-κB(p65)/RelA in infected cells resulted in a 17-fold reduction in HCV RNA. In conclusion, HCV RNA replication was significantly augmented by the inhibition of IKK activation and subsequent NF-κB signalling, whereas a restoration of NF-κB activity by the addition of NF-κB/RelA markedly reduced HCV replication. This study lends added importance to the role of the NF-κB signalling pathway in controlling HCV replication.
Collapse
Affiliation(s)
- E Rance
- Laboratory of Viral Pathogenesis, Research Center, Sainte-Justine University Hospital, Montreal, QC, Canada
| | | | | |
Collapse
|
|
35
|
Popovic M, Bella J, Zlatev V, Hodnik V, Anderluh G, Barlow PN, Pintar A, Pongor S. The interaction of Jagged-1 cytoplasmic tail with afadin PDZ domain is local, folding-independent, and tuned by phosphorylation. J Mol Recognit 2011; 24:245-53. [DOI: 10.1002/jmr.1042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
|
36
|
Li FB, Chen J, Yu JD, Gao H, Qi M. A Chinese girl molecularly diagnosed with Alagille syndrome. World J Pediatr 2010; 6:278-80. [PMID: 20706826 DOI: 10.1007/s12519-010-0226-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 07/12/2010] [Indexed: 11/26/2022]
Abstract
BACKGROUND Alagille syndrome (AGS) is a rare or fatal disease affecting multiple systems including the liver, heart, eyes, skeleton and face. It has been considered a genetically heterogeneous disorder of the Notch signaling pathway. METHODS A 28-month-old Chinese girl with congenital heart disease and jaundice was diagnosed with Alagille syndrome by liver biopsy showing a paucity of the intrahepatic bile ducts. Variants of the JAG1 gene were detected by DNA sequencing in the patient and her unaffected father. RESULTS A heterozygous missense mutation was identified in exon 2 of the JAG1 gene in the proband but not in exon 2, 4, 6, 9, 17, 23, 24 by DNA sequencing in her father. The mutation G-->T change was seen at position 133 in the cDNA sequence (c.133 G-->T), causing a substitution of a leucine for a valine (V45L) residue in the N terminus between signal peptide and DSL domain of the Notch ligand. This mutation, however, was absent in her father. CONCLUSION Genes in the Notch signaling pathway should be further studied in AGS, and used to confirm clinical or prenatal diagnosis and facilitate genetic counseling.
Collapse
Affiliation(s)
- Fu-Bang Li
- Department of Gastroenterology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | | | | | | | | |
Collapse
|
|
37
|
Bauer RC, Laney AO, Smith R, Gerfen J, Morrissette JJD, Woyciechowski S, Garbarini J, Loomes KM, Krantz ID, Urban Z, Gelb BD, Goldmuntz E, Spinner NB. Jagged1 (JAG1) mutations in patients with tetralogy of Fallot or pulmonic stenosis. Hum Mutat 2010; 31:594-601. [PMID: 20437614 DOI: 10.1002/humu.21231] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mutations in the Notch pathway ligand Jagged1 (JAG1) cause Alagille syndrome (AGS), as well as cardiac defects in seemingly nonsyndromic individuals. To estimate the frequency of JAG1 mutations in cases with right-sided cardiac defects not otherwise diagnosed with AGS, we screened 94 cases with tetralogy of Fallot (TOF) and 50 with pulmonic stenosis/peripheral pulmonary stenosis (PS/PPS) or pulmonary valve atresia with intact ventricular septum (PA) for mutations. Sequence changes were identified in three TOF and three PS/PPS/PA patients, that were not present in 100 controls. We identified one frameshift and two missense mutations in the TOF cases, and one frameshift and two missense mutations in cases with PS/PPS/PA. The four missense mutations were assayed for their effect on protein localization, posttranslational modification, and ability to activate Notch signaling. The missense mutants displayed heterogeneous behavior in these assays, some with complete haploinsufficiency, suggesting that there are additional modifiers leading to organ specific features. We identified functionally significant mutations in 2% (2/94) of TOF patients and 4% (2/50) of PS/PPS/PA patients. Patients with right-sided cardiac defects should be carefully screened for features of AGS or a family history of cardiac defects that might suggest the presence of a JAG1 mutation.
Collapse
Affiliation(s)
- Robert C Bauer
- Department of Pediatrics, The Children's Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
|
38
|
Zong Y, Stanger BZ. Molecular mechanisms of bile duct development. Int J Biochem Cell Biol 2010; 43:257-64. [PMID: 20601079 DOI: 10.1016/j.biocel.2010.06.020] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 04/12/2010] [Accepted: 06/22/2010] [Indexed: 12/11/2022]
Abstract
The mammalian biliary system, consisting of the intrahepatic and extrahepatic bile ducts, is responsible for transporting bile from the liver to the intestine. Bile duct dysfunction, as is seen in some congenital biliary diseases such as Alagille syndrome and biliary atresia, can lead to the accumulation of bile in the liver, preventing the excretion of detoxification products and ultimately leading to liver damage. Bile duct formation requires coordinated cell-cell interactions, resulting in the regulation of cell differentiation and morphogenesis. Multiple signaling molecules and transcription factors have been identified as important regulators of bile duct development. This review summarizes recent progress in the field. Insights gained from studies of the molecular mechanisms of bile duct development have the potential to reveal novel mechanisms of differentiation and morphogenesis in addition to potential targets for therapy of bile duct disorders.
Collapse
Affiliation(s)
- Yiwei Zong
- Department of Medicine, Abramson Family Cancer Research Institute, University of Pennsylvania, School of Medicine, Philadelphia, PA, USA
| | | |
Collapse
|
|
39
|
Singh R, Kulkarni K, Kaur G, Thapa BR, Prasad R. Coexistence of Duarte 1 and Duarte 2 variants of galactosemia with extrahepatic biliary atresia. Health (London) 2010. [DOI: 10.4236/health.2010.24041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
|
40
|
Mieli-Vergani G, Vergani D. Biliary atresia. Semin Immunopathol 2009; 31:371-81. [PMID: 19533128 DOI: 10.1007/s00281-009-0171-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 06/01/2009] [Indexed: 12/17/2022]
Abstract
Biliary atresia (BA) is a condition unique to infancy. It results from inflammatory destruction of the intrahepatic and extrahepatic bile ducts. It is the most frequent surgically correctable liver disorder in infancy and the most frequent indication for liver transplantation in paediatric age. Clinical presentation is in the first few weeks of life with conjugated hyperbilirubinaemia (dark urine and pale stools); other manifestations of liver disease, such as failure to thrive, splenomegaly and ascites, appear only later, when surgery is unlikely to be successful. Hence, all infants with conjugated hyperbilirubinaemia must be urgently referred to specialised centres for appropriate treatment. Success of surgery depends on the age at which it is performed. With corrective surgery, followed, when necessary, by liver transplantation, the overall survival rate is approximately 90%. The cause of BA is unknown, but there is evidence for the involvement of infectious, genetic and immunologic mechanisms, which will be discussed in this review.
Collapse
Affiliation(s)
- Giorgina Mieli-Vergani
- Paediatric Liver Centre, Institute of Liver Studies, King's College London School of Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
| | | |
Collapse
|
|
41
|
Cordle J, Johnson S, Tay JZY, Roversi P, Wilkin M, Hernandez-Diaz B, Shimizu H, Jensen S, Whiteman P, Jin B, Redfield C, Baron M, Lea SM, Handford PA. A conserved face of the Jagged/Serrate DSL domain is involved in Notch trans-activation and cis-inhibition. Nat Struct Mol Biol 2008; 15:849-57. [PMID: 18660822 PMCID: PMC2669539 DOI: 10.1038/nsmb.1457] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 06/05/2008] [Indexed: 12/28/2022]
Abstract
The Notch receptor and its ligands are key components in a core metazoan signaling pathway that regulates the spatial patterning, timing and outcome of many cell-fate decisions. Ligands contain a disulfide-rich Delta/Serrate/LAG-2 (DSL) domain required for Notch trans-activation or cis-inhibition. Here we report the X-ray structure of a receptor binding region of a Notch ligand, the DSL-EGF3 domains of human Jagged-1 (J-1(DSL-EGF3)). The structure reveals a highly conserved face of the DSL domain, and we show, by functional analysis of Drosophila melanogster ligand mutants, that this surface is required for both cis- and trans-regulatory interactions with Notch. We also identify, using NMR, a surface of Notch-1 involved in J-1(DSL-EGF3) binding. Our data imply that cis- and trans-regulation may occur through the formation of structurally distinct complexes that, unexpectedly, involve the same surfaces on both ligand and receptor.
Collapse
Affiliation(s)
- Jemima Cordle
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Joyce Zi Yan Tay
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Pietro Roversi
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Marian Wilkin
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Stopford Road, Manchester M13 9PT, UK
| | - Beatriz Hernandez-Diaz
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Stopford Road, Manchester M13 9PT, UK
| | - Hideyuki Shimizu
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Stopford Road, Manchester M13 9PT, UK
| | - Sacha Jensen
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Pat Whiteman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Boquan Jin
- Department of Immunology, Fourth Military Medical University, 17 West Changle Road, Xi’an, Shaanxi 710032, PR China
| | - Christina Redfield
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Martin Baron
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Stopford Road, Manchester M13 9PT, UK
| | - Susan M. Lea
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Penny A. Handford
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| |
Collapse
|
|
42
|
Affiliation(s)
- Benjamin L Shneider
- Department of Pediatrics, Thomas E. Starzl Transplantation Institute, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
| | | |
Collapse
|
|
43
|
Sokol RJ, Shepherd RW, Superina R, Bezerra JA, Robuck P, Hoofnagle JH. Screening and outcomes in biliary atresia: summary of a National Institutes of Health workshop. Hepatology 2007; 46:566-81. [PMID: 17661405 PMCID: PMC3888317 DOI: 10.1002/hep.21790] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Biliary atresia is the most common cause of end-stage liver disease in the infant and is the leading pediatric indication for liver transplantation in the United States. Earlier diagnosis (<30-45 days of life) is associated with improved outcomes following the Kasai portoenterostomy and longer survival with the native liver. However, establishing this diagnosis is problematic because of its rarity, the much more common indirect hyperbilirubinemia that occurs in the newborn period, and the schedule for routine infant health care visits in the United States. The pathogenesis of biliary atresia appears to involve immune-mediated fibro-obliteration of the extrahepatic and intrahepatic biliary tree in most patients and defective morphogenesis of the biliary system in the remainder. The determinants of the outcome of portoenterostomy include the age at surgery, the center's experience, the presence of associated congenital anomalies, and the postoperative occurrence of cholangitis. A number of screening strategies in infants have been studied. The most promising are early measurements of serum conjugated bilirubin and a stool color card given to new parents that alerts them and their primary care provider to alcholic stools. This report summarizes a National Institutes of Health workshop held on September 12 and 13, 2006, in Bethesda, MD, that addressed the issues of outcomes, screening, and pathogenesis of biliary atresia.
Collapse
Affiliation(s)
- Ronald J Sokol
- Department of Pediatrics, University of Colorado School of Medicine, The Children's Hospital, Denver, CO, USA.
| | | | | | | | | | | |
Collapse
|
|
44
|
Liu C, Aronow BJ, Jegga AG, Wang N, Miethke A, Mourya R, Bezerra JA. Novel resequencing chip customized to diagnose mutations in patients with inherited syndromes of intrahepatic cholestasis. Gastroenterology 2007; 132:119-26. [PMID: 17241866 PMCID: PMC2190109 DOI: 10.1053/j.gastro.2006.10.034] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Accepted: 10/05/2006] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Inherited syndromes of intrahepatic cholestasis commonly result from mutations in the genes SERPINA1 (alpha(1)-antitrypsin deficiency), JAG1 (Alagille syndrome), ATP8B1 (progressive familial intrahepatic cholestasis type 1 [PFIC1]), ABCB11 (PFIC2), and ABCB4 (PFIC3). However, the large gene sizes and lack of mutational hotspots make it difficult to survey for disease-causing mutations in clinical practice. Here, we aimed to develop a technological tool that reads out the nucleotide sequence of these genes rapidly and accurately. METHODS 25-mer nucleotide probes were designed to identify each base for all exons, 10 bases of intronic sequence bordering exons, 280-500 bases upstream from the first exon for each gene, and 350 bases of the second intron of the JAG1 gene and tiled using the Affymetrix resequencing platform. We then developed high-fidelity polymerase chain reactions to produce amplicons using 1 mL of blood from each subject; amplicons were hybridized to the chip, and nucleotide calls were validated by standard capillary sequencing methods. RESULTS Hybridization of amplicons with the chip produced a high nucleotide sequence readout for all 5 genes in a single assay, with an automated call rate of 93.5% (range, 90.3%-95.7%). The accuracy of nucleotide calls was 99.99% when compared with capillary sequencing. Testing the chip on subjects with cholestatic syndromes identified disease-causing mutations in SERPINA1, JAG1, ATP8B1, ABCB11, or ABCB4. CONCLUSIONS The resequencing chip efficiently reads SERPINA1, JAG1, ATP8B1, ABCB11, and ABCB4 with a high call rate and accuracy in one assay and identifies disease-causing mutations.
Collapse
Affiliation(s)
- Cong Liu
- Cincinnati Children's Hospital Medical Center and Department of Pediatrics, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | | | | | | | | | | | | |
Collapse
|
|
45
|
Muise AM, Turner D, Wine E, Kim P, Marcon M, Ling SC. Biliary atresia with choledochal cyst: implications for classification. Clin Gastroenterol Hepatol 2006; 4:1411-4. [PMID: 16979949 DOI: 10.1016/j.cgh.2006.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS To illustrate the limitations of the embryonic and perinatal classification system of biliary atresia (BA), we present a child with an antenatal diagnosis of choledochal cyst (CC) associated with BA and review the published literature. METHODS Medline and Pubmed were searched for "BA and CC," "cystic biliary atresia," "BA and cysts," and "biliary cystic malformations." RESULTS A 7-week-old with an antenatal diagnosis of CC was found to have BA associated with CC. The literature search identified 88 cases of BA with CC. Sixty-seven cases had type 1 BA (atresia of the common bile duct), 2 had type 2 BA (atresia of the common hepatic duct), and 19 had type 3 BA (atresia of the porta hepatis). Of the 27 cases of antenatal diagnosis of BA with CC only 1 had associated congenital anomalies. Outcome analysis showed poor outcomes were significantly more common (P = .009) and occurred earlier (P = .0249) in patients with type 3 BA. Children with type 3 BA were 5.4 times more likely to develop poor outcomes compared with type 1 (hazard ratio, 5.4; 95% confidence interval, 1.03-27.8). CONCLUSIONS BA associated with CC forms a distinct subtype of BA, characterized by a preponderance of type 1 BA, a relatively good clinical outcome after surgery, and an absence of associated congenital anomalies. Antenatal diagnosis of many affected infants supports their inclusion within the embryonic BA group and suggests that a broader interpretation of the embryonic phenotype and further classification of BA based on genetic susceptibility may be required.
Collapse
Affiliation(s)
- Aleixo M Muise
- Division of Gastroenterology, Hepatology & Nutrition, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
|
46
|
Rakheja D, Maitra A, Kapur P, Weinberg AG. Extrahepatic biliary atresia demonstrates abnormal persistence of HES1 protein in neonatal biliary epithelium: an immunohistochemical study. Pediatr Dev Pathol 2006; 9:98-102. [PMID: 16822088 DOI: 10.2350/04-12-0135.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 08/18/2005] [Indexed: 11/20/2022]
Abstract
Extrahepatic biliary atresia (EHBA) is an important cause of conjugated hyperbilirubinemia in neonates. It is a progressive disease with a poor prognosis, requiring early surgical intervention to control morbidity and mortality. The exact pathogenesis of this disorder is not known, although genetic, infectious, toxic, and/or environmental factors are thought to play a role in the causation. The Notch signaling pathway plays diverse and critical roles in development of extrahepatic and intrahepatic biliary tree. The HES family of bHLH proteins is involved in downstream signaling in the Notch pathway. We demonstrate that HES1, a principal member of this family, is normally expressed in the nuclei of human biliary epithelial cells up to 16 weeks of gestation, but not in later gestation or in the neonatal period. On the contrary, in EHBA, there is anomalous persistence of this protein for up to 3 months of postnatal life. We suggest that aberrant HES1 expression in EHBA may represent a compensatory feedback upregulation due to a putative downstream molecular defect. Further studies should be performed to evaluate the role of HES1 immunohistochemistry as a diagnostic tool in extrahepatic biliary atresia.
Collapse
Affiliation(s)
- Dinesh Rakheja
- Department of Pathology, Children's Medical Center and University of Texas Southwestern Medical Center, Dallas, USA
| | | | | | | |
Collapse
|
|
47
|
Yuan ZR, Kobayashi N, Kohsaka T. Human Jagged 1 mutants cause liver defect in Alagille syndrome by overexpression of hepatocyte growth factor. J Mol Biol 2005; 356:559-68. [PMID: 16403414 DOI: 10.1016/j.jmb.2005.11.097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 11/29/2005] [Accepted: 11/30/2005] [Indexed: 10/25/2022]
Abstract
Alagille syndrome (AGS, MIM 118450) is an autosomal dominant inherited disease. Paucity of interlobular bile ducts is one of the major abnormalities. To explore the molecular mechanism by which mutation in the human Jagged 1 gene (JAG1, MIM 601920) causes liver defects, we investigated the gene regulation of JAG1 to hepatocyte growth factor gene (HGF). By transfecting wild-type and mutant JAG1 into COS-7 cells in vitro, we found that HGF is a target gene of JAG1 downstream. Wild-type JAG1 is inhibitory for HGF expression and mutant JAG1s relieve the inhibition. Several domain disruptions in mutant JAG1 protein reveal a reduced inhibition to HGF expression at different levels. JAG1 mutations actually result in HGF overexpression. Furthermore, JAG1 controls HGF expression by a dosage-dependent regulation and Notch2 signaling seems to mediate JAG1 function. Given that HGF plays a critical role in differentiation of hepatic stem cells, overexpression of HGF acts on off-balanced cell fate determination in AGS patients. Hepatic stem cells may differentiate towards more hepatocytes but less biliary cells, thus causing the paucity of interlobular bile ducts in liver development of AGS. Our novel findings demonstrated that dosage-dependent regulation by mutations of JAG1 is a fundamental mechanism for liver abnormality in AGS.
Collapse
Affiliation(s)
- Zeng-Rong Yuan
- National Children's Medical Research Center and National Children's Hospital, Tokyo 154, Japan.
| | | | | |
Collapse
|
|
48
|
Abstract
Biliary atresia is the most common cause of neonatal cholestasis and the leading indication for pediatric liver transplantation worldwide. The disease is caused by a progressive inflammatory and fibrosing obliteration of the extrahepatic bile ducts. Although the cause of this obstruction is largely unknown, patient-based studies have identified environmental and genetic factors that may interact and orchestrate disease pathogenesis. Chief among these factors are infectious and immunologic processes. While infectious agents have varied in different patient populations, studies of liver specimens at different phases of disease point to a pro-inflammatory commitment of lymphocytes at the time of diagnosis, and to their potential role in regulating bile duct obstruction. A review of these studies is the focus of this article.
Collapse
Affiliation(s)
- Jorge A Bezerra
- Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, OH 45229, USA.
| |
Collapse
|
|
49
|
Abstract
Biliary atresia (BA) is the most common and important neonatal hepatobiliary disorder. Because current treatment is inadequate, there is an urgent need to better understand the etiology and pathogenesis of BA. Two major forms of BA are recognized: an embryonic form associated with other congenital anomalies and a perinatal form in which bile ducts were presumably formed normally but underwent fibro-obliteration in the perinatal period. There are currently several proposed pathogenic pathways leading to the phenotype of BA, including an immune or autoimmune response to a perinatal insult (e.g. cholangiotropic viral infection) and dysregulated embryonic development of the extra- or intrahepatic biliary system. Recent advances in developmental biology, genomics and genetics, and cell immunology and biology, coupled with the development of appropriate animal models, have provided support for these postulated mechanisms. Future investigations combining animal model work and evaluation of clinical specimens holds the promise of identifying the etiology of BA and providing a scientific basis for treatment and preventative interventions.
Collapse
Affiliation(s)
- Cara L Mack
- Pediatric Liver Center and Liver Transplantation Program, Section of Pediatric Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, University of Colorado School of Medicine and The Children's Hospital, Denver 80218, USA
| | | |
Collapse
|
|
50
|
Lalani SR, Safiullah AM, Fernbach SD, Phillips M, Bacino CA, Molinari LM, Glass NL, Towbin JA, Craigen WJ, Belmont JW. SNP genotyping to screen for a common deletion in CHARGE syndrome. BMC MEDICAL GENETICS 2005; 6:8. [PMID: 15710038 PMCID: PMC550653 DOI: 10.1186/1471-2350-6-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 02/14/2005] [Indexed: 11/24/2022]
Abstract
Background CHARGE syndrome is a complex of birth defects including coloboma, choanal atresia, ear malformations and deafness, cardiac defects, and growth delay. We have previously hypothesized that CHARGE syndrome could be caused by unidentified genomic microdeletion, but no such deletion was detected using short tandem repeat (STR) markers spaced an average of 5 cM apart. Recently, microdeletion at 8q12 locus was reported in two patients with CHARGE, although point mutation in CHD7 on chromosome 8 was the underlying etiology in most of the affected patients. Methods We have extended our previous study by employing a much higher density of SNP markers (3258) with an average spacing of approximately 800 kb. These SNP markers are diallelic and, therefore, have much different properties for detection of deletions than STRs. Results A global error rate estimate was produced based on Mendelian inconsistency. One marker, rs431722 exceeded the expected frequency of inconsistencies, but no deletion could be demonstrated after retesting the 4 inconsistent pedigrees with local flanking markers or by FISH with the corresponding BAC clone. Expected deletion detection (EDD) was used to assess the coverage of specific intervals over the genome by deriving the probability of detecting a common loss of heterozygosity event over each genomic interval. This analysis estimated the fraction of unobserved deletions, taking into account the allele frequencies at the SNPs, the known marker spacing and sample size. Conclusions The results of our genotyping indicate that more than 35% of the genome is included in regions with very low probability of a deletion of at least 2 Mb.
Collapse
Affiliation(s)
- Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Arsalan M Safiullah
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Susan D Fernbach
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, Texas, USA
| | - Michael Phillips
- Genome Quebec and McGill University Innovation Centre, McGill University, Montreal, Quebec, Canada
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Laura M Molinari
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Nancy L Glass
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas, USA
| | - Jeffrey A Towbin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, Texas, USA
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - John W Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|