Late-onset Leigh syndrome without delayed development in China: A case report

Abstract

BACKGROUND

Leigh syndrome (LS) is one of the most common mitochondrial diseases in infants and children. LS often manifests as early-onset with delayed phenotypic development. However, late-onset LS with normal development and white matter lesions in the brain is rarely reported, thereby highlighting the phenotypic variability of LS expression.

CASE SUMMARY

We report a 12-year-old boy who presented with an unusual late-onset and fulminant form of LS that is maternally inherited without developmental delay. The patient was admitted to the hospital with symptoms of ptosis and somnolence, and died within 2 mo. Analysis of peripheral blood leukocytes showed a homoplasmic m.9176T>C mutation in the patient. Magnetic resonance imaging also revealed lesions in bilateral white matter as well as symmetrical lesions in the basal ganglia and brain stem. The patient was diagnosed with LS. The patient was treated with vitamin C, vitamin D, and adenosine-triphosphate. The patient died within 2 mo of hospital admission.

CONCLUSION

LS can present in both infants and older children with different phenotypes.

Keywords: Leigh syndrome; 9176 mutation; Late-onset; Case report

Core Tip: Leigh syndrome (LS) often manifests as early-onset with delayed phenotypic development. However, late-onset LS with normal development and white matter lesions in the brain is rarely reported. Here, we present a late-onset LS case of a previously healthy12-year-old boy that suddenly and unexpectedly died within 2 mo after the onset of symptoms that included myasthenia oculi and subsequent energy failure. Gene analysis revealed that the boy had a T-to-C transition at nucleotide 9176 of the mitochondrial adenosine triphosphatase 6 gene. The current case is reported for the first time in China and highlights the variability of phenotypic expression of LS.