Movement Disorders USMLE Step 1 Practice Question
A 52-year-old woman with a 10-year history of involuntary, irregular jerking movements of the arms and legs develops progressive cognitive decline and mood disturbances. Brain MRI shows atrophy of the caudate nucleus. Genetic testing reveals a CAG trinucleotide repeat expansion on chromosome 4. Which of the following is the most likely diagnosis?
Answer choices
- AFragile X-associated tremor/ataxia syndrome
- BSpinocerebellar ataxia
- CHuntington diseaseCorrect answer
- DParkinson disease
- ESydenham chorea
- FDentatorubral-pallidoluysian atrophy
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.