What is Charcot-Marie-Tooth (CMT) disease type 1B?

Updated: Feb 19, 2019
  • Author: Francisco de Assis Aquino Gondim, MD, MSc, PhD, FAAN; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

Answer

As expected, instances exist of heterozygous CMT1B parents with children with DSS or CHN due to a homozygous or compound heterozygous myelin protein zero mutation. Particular severe forms with onset at age 2 years have been reported with 2 mutations in different domains of MPZ. Some point mutations result in a surprisingly mild phenotype with late onset and relatively faster nerve conduction velocities. A mild phenotype, which was recurrent in response to intense manual labor, not unlike HNPP, has been reported.

Some MPZ mutations are associated with a steroid-responsive neuropathy. Others lead to CMT with relatively faster conduction velocities, dysphagia, deafness, and pupillary abnormalities.


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