skip to main content

Huntington's disease — SCE Neurology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateMovement DisordersHuntington's diseaseSCE Neurology

A 44-year-old woman has progressive chorea, irritability and impaired executive function. Her father died after a similar illness. Examination shows motor impersistence and saccadic initiation delay. Genetic testing confirms an expanded CAG repeat in HTT. What is the most likely underlying mechanism?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Polyglutamine repeat expansion

Polyglutamine repeat expansion is the best answer. Huntington's disease is caused by expanded CAG repeats in HTT, producing a polyglutamine expansion. Mitochondrial deletion, dopamine beta-hydroxylase deficiency, NOTCH3 mutation and copper transport failure fit different disorders. Clinical pearl: Anticipation can occur, especially with paternal transmission.

Reference: ABN Huntington's disease guidance; GeneReviews Huntington disease