Leber’s hereditary optic neuropathy (LHON), a maternally inherited blinding disorder, is associated with three common mitochondrial DNA (mtDNA) point mutations affecting complex I (m.3460G>A/MT-ND1, m.11778G>A/MT-ND4, m.14484T>C/MT-ND6) in 90% of cases [1]. Here, MT-ND4 is linked to Leber hereditary optic neuropathy.