ND5 mutations have been reported in many mitochondrial diseases such as Leber’s hereditary optic neuropathy (LHON)41, mitochondrial encephalopathy40, mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes (MELAS)42, myoclonic epilepsy with ragged red fibres (MERRF)43, and Leigh syndrome44. The gene discussed is MT-ND5; the disease is mitochondrial disease.