What is the pathophysiology of Charcot-Marie-Tooth type 1B (CMT1B)?

Updated: May 22, 2018
  • Author: Timothy C Parsons, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Myelin protein zero is an integral type I membrane protein, and is the most abundant structural protein of compact peripheral nerve myelin. [39, 15]

More than 80 mutations in myelin protein zero have been described. Most are associated with the typical CMT1B phenotype, but correlations have been found with other clinical phenotypes including CMT2, Dejerine Sottas syndrome, and congenital hypomyelination neuropathy. [40, 41]

Predominantly axonal and predominantly demyelinating forms appear to be due to different mutations in the same gene. Mutations that introduce a charged amino acid, removed or added a cysteine residue, or altered an evolutionarily conserved amino acid alter the tertiary structure of the MPZ protein as a result and lead to the more severe early onset phenotype. As with diseases of PMP22 expression, the mechanism for either demyelinating or axonal forms remains unclear, but may be due to impaired myelin-axon interaction. [42, 43, 44]

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