These genetic changes are maternally inherited because they are located in the mtDNA, which is passed down from the mother. MT-ND5 mutations can cause a broad range of mitochondrial encephalopathies, such as mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Leigh syndrome, Leber hereditary auditory neuropathy (LHON), or other nonspecific neurodegenerative syndromes [3]. The gene discussed is MT-ND5; the disease is Leber hereditary optic neuropathy.