MT-ND4 and Leber hereditary optic neuropathy: Definitive diagnosis of LHON is achieved by the molecular identification of one of the three mtDNA mutations (m.11778G.A/MT-ND4, m.3460G.A/MT-ND1, m.14484T.C/MT-ND6), which account for about 90% of cases [14,22].