NADH Dehydrogenase 5 (ND5)

The MT-ND5 is part of a large enzyme complex known as complex I, which is active in mitochondria. Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Mutations in the MT-ND5 gene are responsible for a small percentage of all cases of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. These mutations alter single DNA building blocks (nucleotides) in the gene. A particular mutation has been identified in at least five people with the characteristic features of MELAS; this mutation replaces the nucleotide guanine with the nucleotide adenine at gene position 13513. Most of the MT-ND5 mutations that cause MELAS have been shown to reduce the activity of complex I, which disrupts energy production within mitochondria.