Charcot-Marie-Tooth (CMT)

1. What is the presentation of Hereditary Motor Sensory Neuropathy I (HMSN-I, Charcot-Marie-Tooth)?
2. What are the lab findings in CMT?
3. What are the EMG findings in CMT?
4. What is the treatment for CMT?

Answers:
1. CMT is an autosomal dominant disease that presents in early childhood. It is slowly progressive and sensory loss is more apparent in LEs than UEs, there is abnormal vibration and proprioception, intrinsic foot atrophy resulting in pes cavus and hammer toes, bilateral foot drop resulting in steppage gait, stork leg appearance, and essential tremor.
2. CSF has increased protein. Nerve biopsy shows onion bulb formation.
3. SNAP is abnormal. CMAP is abnormal with CV less than 70% of normal. EMG may be normal or show signs of reinnervation.
4. Treatment is rehab and orthotics.