Last updated 2mo ago
Log in to add personal notes on this page.
A teenager with high arches (pes cavus) and hammer toes has slowly progressive distal weakness and sensory loss. NCVs show uniformly slow motor conduction velocities.
AD; PMP22 duplication (1.4 Mb on 17p12) - 70% of CMT1
- Distal muscle weakness and atrophy ("stork legs")
- Pes cavus, hammer toes
- Sensory loss
- Areflexia
- Nerve conduction: demyelinating (slow velocities)
- CMT1A: most common CMT, onset first two decades
- Nerve conduction studies show uniformly slowed motor velocities (demyelinating range), pointing to CMT1
- Targeted PMP22 duplication testing (MLPA or dosage analysis) confirms CMT1A; reflex to a neuropathy panel if negative
- The 1.4 Mb 17p12 duplication arises from nonallelic homologous recombination; the reciprocal deletion causes HNPP
- Cascade testing of at-risk relatives and reproductive counseling once the duplication is confirmed (autosomal dominant)
- No cure; supportive care centered on PT/OT, ankle-foot orthoses, and physical activity to maintain function
- Foot care and orthopedic management for pes cavus, hammer toes, and contractures (surgery in selected cases)
- Avoid neurotoxic agents (for example vincristine), which can precipitate severe worsening
- Multidisciplinary follow-up with monitoring for fatigue, pain, and mobility decline
"CHARCOT": (pes) Cavus, Hyperproliferation of Schwann cells, Autosomal dominant, Reflexes lost (deep tendon), CMT1A (most common form, PMP22), Onion bulb appearance, Thickening of nerve