Missense mutations in the NDUFS3 gene have been linked to various diseases, such as Leigh syndrome, and deficiency of NDUFS3 can result in mitochondrial myopathy and optic atrophy.[11, 12] These prior findings underscore the critical importance of an appropriate structure and composition for the biogenesis and assembly of CI. The gene discussed is NDUFS3; the disease is hereditary optic atrophy.