Charcot-Marie-Tooth Disease (3)

Question 1

What are the types of it?

Answer 1

• Type 1 (60%) – CMT1 mutation (Demyelinating)
• Type 2 (30%) – CMT2 mutation (Axonal)
10% mixed

Question 2

When does it usually present?

How does it present?

Answer 2

➊ During puberty as the disease is length-dependent

➋ • Slowly progressive distal symmetrical sensorimotor polyneuropathy
• Symmetrical, distal muscular atrophy (champagne bottle legs, claw hand)
• Pes cavus (club foot)
• Reduced reflexes and tone

Question 3

How is it investigated?

Answer 3

NCS - Depends on the type of CMT mutation:
• Demyelinating (T1) – ↓nerve conduction velocity
• Axonal (T2) – ↓action potential amplitude