m.3635G>A mutation as a cause of Leber hereditary optic neuropathy

Over 90% of Leber's hereditary optic neuropathy (LHON) is caused by one of three mtDNA mutations (m.11778A>G, m.3460G>A, m.14484T>C). The remaining cases are due to rare mutations in different genes encoding subunits of the respiratory chain. The proband is a 17-year-old male with symptoms of optic nerve atrophy. No common LHON mutations were found, but detailed sequencing identified a rare, homoplasmic mutation m.3635G>A in the ND1 gene.