MT-ND4 and Leber hereditary optic neuropathy: In LHON patients, the 11778G > A mutation impacts a crucial amino acid in the NADH dioxygenase subunit 4 complex 1 (ND4) gene, and therefore, intravitreal injection of rAAV2/2-ND4 is an effective method for the treatment of LHON (3).