Transcription factor that binds and activates the promoter of thyroid specific genes such as thyroglobulin, thyroperoxidase, and thyrotropin receptor. Crucial in the maintenance of the thyroid differentiation phenotype. May play a role in lung development and surfactant homeostasis. Defects in NKX2-1 are the cause of benign hereditary chorea (BHC); also known as hereditary chorea without dementia. BHC is an autosomal dominant movement disorder. The early onset of symptoms (usully before the age of 5) and the observation that in some BHC families the symptoms tend to decrease in adulthood suggests that the disorder results from a developmental disturbance of the brain. BHC is non-progressive and patients have normal or slightly below normal intelligence. There is considerable inter- and intrafamilial variability, including dysarthria, axial distonia and gait disturbances. Defects in NKX2-1 are the cause of choreoathetosis, hypothyroidism, and neonatal respiratory distress (CHNRD). This syndrome include neurological, thyroid, and respiratory problems. Belongs to the NK-2 homeobox family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.