Which neurodegenerative disease is characterized by early chorea, psychiatric symptoms, and autosomal dominant inheritance?

• A. Alzheimer disease
• B. Parkinson disease
• C. Huntington disease
• D. Amyotrophic lateral sclerosis

Answer: (C)

Early chorea with psychiatric symptoms and autosomal dominant inheritance is classic for Huntington disease. This neurodegenerative disorder is caused by a CAG trinucleotide repeat expansion in the HTT gene on chromosome 4, leading to a toxic huntingtin protein. The disease primarily affects the striatum (caudate and putamen), causing choreiform movements, along with prominent behavioral and psychiatric changes that often appear early. Because the mutation is autosomal dominant with full penetrance and anticipation (repeating expansion tends to worsen in successive generations), this pattern of inheritance is a defining feature.

Alzheimer disease centers on progressive memory loss and cognitive decline with characteristic amyloid and tau pathology, not early chorea. Parkinson disease features resting tremor, bradykinesia, and rigidity with dopaminergic loss, not early chorea and dominant inheritance as a hallmark. Amyotrophic lateral sclerosis presents with motor neuron signs (weakness, fasciculations, spasticity) rather than chorea and prominent psychiatric early symptoms.