It is characterized by bilateral, subacute, painless vision loss, and more than 95% of cases of LHON are caused by 1 of 3 mitochondrial DNA (mtDNA) point mutations: 3460 G > A, 11778 G > A, and 14484 T > C or mutation in the TMEM126A gene encoding a mitochondrial protein. This evidence concerns the gene TMEM126A and Leber hereditary optic neuropathy.