Charcot-Marie-Tooth Disease

From Iusmgenetics

Contents 1 Charcot-Marie-Tooth Disease 1.1 General background information 1.2 Mode of inheritance 1.3 Single important gene 1.4 Etiology 1.5 Pathogenesis 1.6 Phenotypic information 1.7 Diagnosis 1.8 Treatment 1.9 Recent research 1.10 5 important facts 1.11 Not to be confused with 1.12 Questions and answers

[edit] Charcot-Marie-Tooth Disease

[edit] General background information

• Charcot-Marie-Tooth disease is also known as "Hereditary motor and sensory neuropathy" (HMSN)

[edit] Mode of inheritance

• There are dominant and recessive types
• Hereditary motor and sensory neuropathy demonstrates variable expressivity
• Type 1 is autosomal dominant (CMT1)

[edit] Single important gene

• The PMP22 gene codes for the structural protein of PNS myelin

[edit] Etiology

• The pmp22 gene is duplicated in 70-80% of cases of CMT1
  • The PMP22 gene is on ch 17.
• Duplication is facilitated by repeat sequences flanking the pmp22 gene which lead to misalignment and duplication.

[edit] Pathogenesis

• Segmental demyelination peripheral nerves
• Demyelination results in altered nerve conduction velocities, hypertrophic changes and "onion bulb" formation
• Altered nerve

[edit] Phenotypic information

• Slowly progressive distal wasting and weakness
  • First in legs: difficulty walking, loss of reflexes, loss of sensation in toes
  • Later in arms

[edit] Diagnosis

[edit] Treatment

[edit] Recent research

[edit] 5 important facts

[edit] Not to be confused with

[edit] Questions and answers