Fact-sheet: Charcot Marie Tooth Disease - Hereditary motor and sensory neuropathy
Updated on 04/23/2019 at 9:57 AM
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Definition
Hereditary sensorimotor peripheral neuropathy.
Two main forms:
- demyelinating form
- axonal form
Prevalence: 1/2500.
Symptom onset generally in childhood or adolescence.
Mode of transmission:
- autosomal dominant
- autosomal recessive
- X-linked dominant
Clinical features
- Hereditary sensorimotor neuropathy
- Motor deficit and limb amyotrophy
- Sensory disturbances
- Loss of deep tendon reflexes
- Pes cavus or pes planus
- Scoliosis
- Chronic, progressive, and ascending course
There is considerable inter-individual and intrafamilial variability.
MRI
Magnetic Resonance has proven useful for assessing the extent and pattern of muscle atrophy, fatty replacement of muscle fibers, and for determining the level of muscle fiber denervation.
Thus, Magnetic Resonance could be used to confirm the findings obtained by manual muscle testing in CMT.
Classification
There are nearly thirty different forms of
Charcot-Marie-Tooth disease, which are classified according to:
1: the mode of genetic transmission: autosomal dominant,
autosomal recessive, X-linked;
2: the nature of the nerve involvement:
• axonal (nerve conduction velocity > 40 ms),
• demyelinating (nerve conduction velocity < 35 m/s)
• mixed (nerve conduction velocity intermediate between
25 m/s and 45 m/s);
3: the underlying genetic abnormalities and the deficient proteins.