Hepatocyte Nuclear Factor 4 alpha (HNF4 alpha; NR2A1) is a member of the orphan nuclear receptor family. HNF4 alpha is expressed in the liver, kidney, intestine and pancreas. Mutation of HNF4 alpha in humans has been associated with maturity-onset diabetes of the young type 1 (MODY1). HNF4 binds to DNA as an exclusive homodimer. The HNF4 alpha gene is alternatively spliced and may generate up to nine different isoforms, HNF4 alpha 1 through HNF4 alpha 9. The expression of HNF-4 gamma (NR2A2) is observed in the pancreas, kidney, small intestine, and testes with no expression detected in the liver. The level of HNF-4 gamma is less 10% than that of HNF-4 alpha.