- See: CMT Menu:
- Discussion:
- autosomal dominant inheritance;
- type-I and III disorders are due to demyelination of peripheral nerves;
- clinical presentation is most common during the second decade of life;
- due to defect in the gene coding for peripheral myelin protein-22 on chromosome 17;
- EMG in demyelinating neuropathies:
- motor nerve-conduction study reveals marked slowing of rate of impulse conduction;
- biopsy:
- biopsy of a distal muscle such as the gastrocnemius demonstrates a neuropathic pattern;
- in pts for whom diagnosis remains unclear, categorization is aided by biopsy of the sural nerve, which demonstrates demyelination;
- Clinical Manifestations:
- symptoms do not manifest until adolescence;
- patients note weakness in the legs followed by weakness in the intrinsics of the hand;
- ataxia
- generalized tendon areflexia
- distal sensory loss (esp light touch, position, and vibration sense);
- hands:
- weakness in hands, upper limb tremor;
- foot:
- mild cavus deformity or clawing of toes may be first clinical manifestation;
- abnormal foot position is initially flexible, but with increasing peroneal involvement, an equinovarus deformity gradually develops;
- pt experiences pain under the lateral metatarsal heads during wt bearing and has difficulty in running;
- look for lateral wear on soles of shoes
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