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Duchenne muscular dystrophy coexisting with Down syndrome or Turner syndrome: Two case reports
Peerada Pongsakornkullachart, Mongkol Chanvanichtrakool, Dhachdanai Dhachpramuk, Theeraphong Pho-Iam, Nattha Yongwattana, Pimchanok Kulsirichawaroj, Jantima Tanboon, Oranee Sanmaneechai
Peerada Pongsakornkullachart, Mongkol Chanvanichtrakool, Pimchanok Kulsirichawaroj, Oranee Sanmaneechai, Division of Neurology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
Mongkol Chanvanichtrakool, Dhachdanai Dhachpramuk, Pimchanok Kulsirichawaroj, Pediatric Precision Medicine Center, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
Dhachdanai Dhachpramuk, Division of Genetics, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
Theeraphong Pho-Iam, Nattha Yongwattana, Siriraj Genomics, Office of the Dean, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
Pimchanok Kulsirichawaroj, Oranee Sanmaneechai, Center of Research Excellence for Neuromuscular Diseases, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
Jantima Tanboon, Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
Author contributions: Pongsakornkullachart P and Kulsirichawaroj P equally contributed to conceptualization; Pongsakornkullachart P and Kulsirichawaroj P collected clinical data and managed patients; Pho-Iam T, Yongwattana N, and Dhachpramuk D performed genetic analysis and interpreted data; Tanboon I supervised the pathological studies; Pongsakornkullachart P curated the data, conducted literature review and drafted the manuscript; Dhachpramuk D, Pho-Iam T, Chanvanichtrakool M, Kulsirichawaroj P, and Sanmaneechai O critically reviewed the manuscript; Kulsirichawaroj P supervised the study, provided clinical oversight; All authors have read and approved the final manuscript.
AI contribution statement: ChatGPT was used only for minor language editing to improve grammar, clarity and readability. The intellectual content, structure and interpretation remained entirely the work of the authors. No portion of the manuscript (abstract, introduction, material and methods, results, discussion and conclusion) was generated by AI. All scientific content and writing were originally produced by authors. Also, AI tools were not involved in the study design, data analysis or interpretation of results.
Informed consent statement: Written informed consent was obtained from the patients’ parents for publication of this case report and accompanying images.
Conflict-of-interest statement: All authors declare that there are no conflicts of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Corresponding author: Pimchanok Kulsirichawaroj, MD, Division of Neurology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok 10700, Thailand.
pimchanok.kul@mahidol.ac.th
Received: November 20, 2025
Revised: December 25, 2025
Accepted: January 26, 2026
Published online: June 9, 2026
Processing time: 175 Days and 4 Hours
BACKGROUND
Dystrophinopathies are X-linked recessive neuromuscular disorders caused by pathogenic variants in the dystrophin gene (DMD). Down syndrome (DS) and Turner syndrome (TS) are well-characterized chromosomal conditions; however, their co-occurrence with monogenic disorders such as Duchenne muscular dystrophy (DMD) is rare and presents unique diagnostic and management challenges.
CASE SUMMARY
We report two rare cases of DMD coexisting with chromosomal abnormalities, both followed at Siriraj Hospital. The first case involved a 6-year-old boy with DS who presented with incidentally detected elevated serum transaminase levels, calf pseudohypertrophy, and gait difficulty; gene panel testing identified a hemizygous c.3917dup (p.Asp1307Argfs*4) variant in DMD. The second case involved a 6-year-old girl with proximal muscle weakness and calf pseudohypertrophy; genetic studies revealed a heterozygous delins variant in the DMD (p.Ala3041Serfs*69), skewed X-chromosome inactivation, and mosaic TS [45,X(29%)/46,XX].
CONCLUSION
The coexisting of DMD with DS or TS produces overlapping phenotypes that can complicate diagnosis; careful genetic evaluation and multidisciplinary management are therefore essential.
Core Tip: This report describes two unprecedented cases of Duchenne muscular dystrophy coexisting with Down syndrome (DS) and Turner syndrome (TS), highlighting the diagnostic challenges at the intersection of chromosomal and monogenic disease. In patient with DS, hypotonia and developmental delay may mask progressive weakness; in females, a heterozygous variant in the dystrophin gene should prompt evaluation for mosaic TS. Next-generation sequencing, guided by clinical suspicion, enabled recognition of these dual genetic diagnoses. These findings broaden the phenotypic spectrum of Duchenne muscular dystrophy and underscore the need for individualized multidisciplinary care.
