This intronless gene belongs to the forkhead family of transcription factors, which is characterized by a distinct forkhead domain. This gene functions as a thyroid transcription factor which likely plays a crucial role in thyroid morphogenesis. Mutations in this gene are associated with congenital hypothyroidism and cleft palate with thyroid dysgenesis. The map localization of this gene suggests it may also be a candidate gene for squamous cell epithelioma and hereditary sensory neuropathy type I.?