NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1 is a protein that in humans is encoded by the NDUFA1 gene. The NDUFA1 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in the NDUFA1 gene are associated with mitochondrial Complex I deficiency.