The protein encoded by the HNF4 gene is a nuclear transcription factor which binds DNA as a homodimer. The encoded protein controls the expression of several genes, including hepatocyte nuclear factor 1 alpha, a transcription factor which regulates the expression of several hepatic genes. This gene may play a role in development of the liver, kidney, and intestines. Mutations in this gene have been associated with monogenic autosomal dominant non insulin dependent diabetes mellitus type I. At least three different transcript variants encoding three different isoforms have been found for this gene.