This gene encodes a subunit of the membrane-bound mitochondrial complex I. Complex I is composed of numerous subunits and functions as the NADH-ubiquinol reductase of the mitochondrial electron transport chain. Mutations in this gene are associated with severe mitochondrial complex I deficiency. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Oct 2010] see less This gene encodes a subunit of the membrane-bound mitochondrial complex I. Complex I is composed of numerous subunits and functions as the NADH-ubiquinol reductase of the mitochondrial electron transport chain. Mutations in this gene are associated with severe mitochondrial complex I deficiency. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Oct 2010]