Movement Disorders USMLE Step 1 Practice Question
A 47-year-old man presents with progressive chorea, irritability, and impulsive aggression affecting work performance. Vital signs: BP 128/82, HR 92, RR 16, Temp 37°C, SpO2 98%. MRI shows mild caudate atrophy. He denies depression or suicidality. Genetic testing confirms expanded CAG repeat in the HTT gene. Which neurotransmitter change is most likely present in the affected striatum early in this disease?
Answer choices
- AIncreased dopamine and decreased GABA in the striatumCorrect answer
- BDecreased glutamate and increased GABA in the cerebellum
- CDecreased dopamine and increased acetylcholine in the substantia nigra
- DIncreased acetylcholine and decreased dopamine in the hippocampus
- EIncreased serotonin and decreased norepinephrine in the locus coeruleus
- FDecreased serotonin and increased glutamate in the prefrontal cortex
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