MT-ND4 and Leber hereditary optic neuropathy: Leber’s Hereditary Optic Neuropathy (LHON), is due to three primary mutations (i.e. m.3460G > A in MT-ND1, m.11778G > A in MT-ND4 and m.14484 T > C MT-ND6) in the mitochondrial DNA (mtDNA) genes, encoding for three different subunits of NADH: ubiquinone oxidoreductase (EC 1.6.5.3) or complex I (CI) for more than 90% of cases [1].