skip to main content

Charcot-Marie-Tooth disease — SCE Neurology MCQ

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

EasyNeuromuscularCharcot-Marie-Tooth diseaseSCE Neurology

A 27-year-old man presented with lifelong pes cavus, distal wasting and family history of foot drop. On examination, there were absent ankle reflexes and glove-stocking sensory loss. Initial investigations showed: NCS showed uniformly slow conduction velocities. 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 — PMP22 duplication causing demyelinating neuropathy

PMP22 duplication causing demyelinating neuropathy is the best answer because the vignette describes Charcot-Marie-Tooth disease: hereditary demyelinating neuropathy with pes cavus suggests CMT1. Small-vessel lipohyalinosis is plausible in a neighbouring presentation, but the chronology, examination or investigation pattern does not match the key discriminator here. Immune-mediated inflammatory demyelination and Paradoxical embolism through a right-to-left shunt are less appropriate because they would require different localisation, timing or test findings; Cortical spreading depolarisation would fit a different syndrome. Clinical pearl: CIDP is acquired and often has conduction block or raised CSF protein.

Reference: NICE NG42; ABN myasthenia gravis guidance; EAN/PNS GBS-CIDP guidance