For example: Huntington’s disease (NDUFA7, NDUFC1, NDUFB2, NDUFB3, NDUFA8) [33], [34], atrophy of optic nerve (NDUFS4) [35] and Leigh syndrome (NDUFS7, NDUFA2, NDUFS4) [36]–[38]. The gene discussed is NDUFA2; the disease is Leigh syndrome.