MT-ND4 and Leber hereditary optic neuropathy: Mutations in OPA1 and MFN2 genes cause autosomal dominant optic atrophy (DOA); mutations in WFS1 and CISD2 can cause Wolfram syndrome, while Leber's hereditary optic neuropathy (LHON) is associated with mutations in mitochondrial ND1, ND4, and ND6 genes [61, 62].