MT-ND6 and Leber hereditary optic neuropathy: Leber's hereditary optic neuropathy (LHON) is a maternally inherited disease, 90% of which is caused by three primary mutation sites, namely, 11778/ND4, 3460/ND1, and 14484/ND6, affecting different subunits of complex I and leading to dysfunction in the mitochondrial respiratory chain (Carelli et al., 2004; Yu-Wai-Man et al., 2009; Giordano et al., 2011).