MT-ND1 and Leber hereditary optic neuropathy: In more than 90% of cases, LHON is caused by one of the common mitochondrial DNA (mtDNA) pathogenic variants (MT-ND4 NC_012920.1:m.11778G>A, MT-ND6 NC_012920.1:m.14484T>C, and MT-ND1 NC_012920.1:m.3460G>A).