OPA1 and Leber hereditary optic neuropathy: At least eight loci (OPA1 to OPA8) have been mapped to the nuclear genome in association with optic atrophy, in which three causative genes have been identified, including the optic atrophy 1 (OPA1, OMIM 605290) gene, the optic atrophy 3 (OPA3, OMIM 606580) gene, and the transmembrane protein 126A (TMEM126A, OMIM 612988) gene [1].