spasticity and cerebellar ataxia. Roughly half of affected patients die of respiratory or cardiac failure by the age of three. Leigh syndrome is a maternally inherited disorder and its diagnosis is established through genetic testing of the aforementioned mitochondrial genes, including MT-ND2. These complex I genes have been associated with a variety of neurodegenerative disorders, including Leber's hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS) and the previously mentioned Leigh syndrome. Mitochondrial dysfunction resulting from variants of MT-ND2, MT-ND1 and MT-ND4L have been linked to BMI in adults and implicated in metabolic disorders including obesity, diabetes and hypertension. References Further reading External links Mass spectrometry characterization of MT-ND2 at COPaKB Proteins Human mitochondrial genes