MT-ND4 and Leber hereditary optic neuropathy: Regarding genetics, in 90% of cases, LHON is caused by three homoplasmic point mutations in the mitochondrial DNA (mtDNA): m.11778G>A in the MT-ND4 gene (the most common one), m.3460G>A in MT-ND1 and m.14484T>C in MT-ND6 [25].