A Video Report of Brain-Lung-Thyroid Syndrome in a Japanese Female With a Novel Frameshift Mutation of the NKX2-1 Gene.

Benign hereditary chorea is a rare autosomal-dominant disorder that is characterized by childhood-onset nonprogressive chorea and normal cognitive function. Defects in NKX2-1 on chromosome 14q13, which encodes thyroid transcription factor 1, produce a concurrent clinical manifestation of chorea, respiratory distress, and hypothyroidism known as "brain-lung-thyroid syndrome." Here, the authors describe a video report of benign hereditary chorea in a Japanese female with a novel frameshift mutation of NKX2-1 (c.915_916insC) (p.Ala303ArgfsX132) that was initially misdiagnosed as ataxic cerebral palsy. In early infancy, especially before the appearance of chorea, benign hereditary chorea can be misdiagnosed as ataxic and dyskinetic cerebral palsy due to shared clinical features including motor delay, hypotonia, ataxic gait, and dystonia.