Charcot-Marie-Tooth disease comprises a group of hereditary peripheral neuropathies with different genetic abnormalities.
Absence of a family history does not rule out the condition.
Key features include clumsiness as a child, weak ankles, symmetrical nerve conduction changes, and a steppage gait (lifting legs up excessively to clear the toes).
Pes cavus (high foot arches with hammertoes) and distal atrophy of the hands and legs are characteristic.
Genetic testing should be carefully considered.
Appropriate rehabilitative and orthotic treatments can keep patients highly functional.
Charcot-Marie-Tooth (CMT) disease, also known as hereditary motor and sensory neuropathy (HMSN), encompasses the majority of hereditary peripheral neuropathies. Both motor and sensory nerves are typically affected, with symmetrical changes noted on nerve conduction studies. Nerve conductions can be either demyelinating (velocity <38 m/second in ulnar nerve), or axonal (reduced amplitudes with >38 m/second velocity), or have features of both. CMT is a genetically heterogeneous condition, with over 90 genes and loci known to cause the condition when mutated.
History and exam
Key diagnostic factors
- family history of neuropathy, pes cavus, or abnormal gait
- walking difficulties
- pes cavus
- steppage gait
- diffuse deep tendon hyporeflexia or areflexia
- reduced muscle strength
- reduced sensation
- transient sensory symptoms
- transient motor symptoms
Other diagnostic factors
- past surgery to feet and ankles
- balance difficulties in childhood
- ankle weakness
- sensory abnormalities in hands and feet
- delayed motor milestones without ambulation
- sensory ataxia
- family history of neuropathy, pes cavus (high foot arches with hammertoes), or abnormal gait
1st investigations to order
- nerve conduction studies (NCS)
Investigations to consider
- genetic testing
- hip x-ray
- pulmonary function testing
- Diabetic neuropathy
- Chronic inflammatory demyelinating polyneuropathy
- Acquired peripheral neuropathy
- Clinical practice guideline for the management of paediatric Charcot-Marie-Tooth disease
- Guidelines for the molecular diagnosis of neurogenetic disorders: motoneuron, peripheral nerve and muscle disorders
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