FOXP1 is a forkhead box (FOX) transcription factor that plays a role in the regulation of tissue- and cell type-specific gene transcription during both development and adulthood. FOXP1 protein contains both DNA-binding- and protein-protein binding-domains, and it acts as a transcriptional repressor. In development, it is required for the proper formation of the brain, heart, lung and muscles in the esophagus. In the heart, it mediates outflow tract separation of the pulmonary artery and aorta as well as cardiac myocyte maturation and proliferation. This gene may also act as a tumor suppressor and is lost in several tumor types. Disruptions in FOXP1 lead to intellectual disability, language impairment, cognitive dysfunction and autism. In immunohistochemistry of normal tissue, FOXP1 has nuclear positivity in a majority of tissues throughout the body. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804;