HNF4α also known as HNF4alpha, HNF4A is a nuclear transcription factor which binds DNA as a homodimer. HNF4α controls the expression of several genes, including hepatocyte nuclear factor 1 alpha, a transcription factor which regulates the expression of several hepatic genes. HNF4α is predominantly expressed in the liver, kidney, pancreas, intestine, testis, and colon, influencing the transcription of numerous hepatocyte-specific genes such as cytochrome P450 enzymes and alpha-1 antitrypsin. Mutations in HNF4α are associated with maturity-onset diabetes of the young type 1 (MODY1), underscoring HNF4α′s importance in maintaining glucose homeostasis. HNF4α interacts with other hepatocyte nuclear factors like HNF1 and HNF3 to regulate gene expression during early embryonic development and organogenesis.