<unk>  is an autosomal dominant disorder. It is believed to be caused by a single-nucleotide substitution in TITF1, located on chromosome 14. A wide spectrum of mutations have been reported, drawing a potential association between amount of subsequently deleted nucleotides to severity of symptoms. These mutations lead to protein truncation, prevent DNA binding, and a loss-of-function. Mutations of the gene affect namely the lungs, brain, and thyroid. This is because during embryonic development, NKX2.1 plays a key role in binding to transcriptional regulatory elements and proteins within those respective organs. Epidemiology In 1978, BHC was reported to have a frequency of 1:500,000 within a Welsh population, but due to how some symptoms are hard to distinguish, it was concluded that the number is underrespresentative of actual clinical cases. Results for correlation between sex and distribution of the disorder are inconclusive.
Benign hereditary chorea
Non-progressive congenital ataxia
Sydenham's chorea
X-linked dystonia parkinsonism
Autosomal recessive cerebellar ataxia
Autosomal recessive cerebellar ataxia type 1
Spinocerebellar ataxia
Huntington's disease-like syndrome