Which symptom is a primary motor symptom of Huntington's disease?

• A. Chorea
• B. Depression
• C. Weight gain
• D. Anxiety

Answer: (A)

Chorea is the main motor finding in Huntington's disease. These involuntary, rapid, irregular, dance-like movements occur because neurons in the striatum (caudate and putamen) deteriorate, especially affecting the indirect pathway of the basal ganglia. This loss reduces inhibitory control over thalamocortical circuits, leading to excessive, uncoordinated movements that can involve the face, limbs, and trunk. While depression, anxiety, and weight changes are common in Huntington's, they are non-motor symptoms. So, the hallmark motor feature that Best identifies the motor phenotype is chorea.