In HD, chorea often appears as facial twitching or as twitching and writhing of the distal extremities. As HD disease progresses, the movement disorder becomes more generalized. Eventually, the patient's gait is impaired. Rigidity and dystonia predominate in later stages of the disease in adults. In juvenile cases, rigidity and dystonia may appear as the initial symptoms.
Symptoms become worse with anxiety or stress.
A mental status examination may reveal depression. Impaired cognitive abilities may be detected on physical examination. HD is a genetic disease inherited as an autosomal dominant trait. The gene is present on chromosome 4. The gene encodes a protein known as huntingtin.