ADI1 and Leber hereditary optic neuropathy: For example, the three point mutations (11778G > A, 14484T > C; 3460G > A) in complex I (MTND) genes that cause Leber hereditary optic neuropathy (LHON) preferentially target the retinal ganglion cell and cause blindness [14]; and the 1555A > G mtDNA 12S rRNA gene mutation causes isolated sensori-neural deafness [15].