🏥 USMLE Exam Prep

A 45-year-old male develops progressive chorea, psychiatric symptoms, and cognitive decline. His father had similar symptoms. Genetic testing reveals an expansion of trinucleotide repeats (CAG) on chromosome 4. This inheritance pattern is consistent with which genetic disorder?

A Cystic fibrosis
B Duchenne muscular dystrophy
C Huntington's disease
D Sickle cell anemia

✓ Correct Answer: Option C

Huntington's disease is an autosomal dominant neurodegenerative disorder caused by an expanded CAG trinucleotide repeat in the huntingtin gene on chromosome 4, leading to progressive motor, cognitive, and psychiatric symptoms.

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