HADH (Hydroxyacyl-Coenzyme A dehydrogenase) is a mitochondrial protein that catalyzes the oxidation of a wide variety of fatty acids, alcohols, and steroids. 3-hydroxyacyl-CoA dehydrogenase type II (HADH2) is a member of the short-chain dehydrogenase/reductase superfamily. HADH 2 is expressed at high levels in Alzheimer’s disease.