What is the role of lab testing in the workup of Charcot-Marie-Tooth (CMT) disease?

Updated: May 22, 2018
  • Author: Timothy C Parsons, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

The workup should be primarily geared toward the identification or exclusion of a treatable neuropathy, including tests that address the causes of neuropathy. If a clear family history is identified and CMT has not been confirmed genetically, genotyping is warranted. Ascertaining the presence of a demyelinating or axonal form with nerve conduction studies, and establishing inheritance pattern with a pedigree can narrow the differential diagnosis and reduce the number of needed tests. De novo mutations are not rare, and genetic counseling can be pursued even in the absence of a family history of neuropathy.

Despite the lack of available treatments, genotyping is useful in providing information for prognosis and genetic counseling. [84]

A negative genetic test does not exclude the diagnosis, especially in axonal forms. Beinfait and colleagues found mutations in only 3 out of 18 families (61 patients) with CMT2, and Bennett and colleagues found no mutations in 6 families with late-onset (median age 57), predominantly axonal neuropathies. [71, 83]


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