July 13, 2015: Charcot-Marie-Tooth
July 13, 2015
Charcot Marie Tooth or "CMT" also known as hereditary motor/sensory neuropathy is a genetic disorder characterized typically by a progressive symmetrical and distal, or length-dependent, peripheral neuropathy. CMT is the most common hereditary neuropathy. Depending upon which genes are involved, the disease can be subclassifed as CMT1, 2, or 4 as well as intermediate form CMT and CMTX, the latter of which is x-linked dominant and affects only men and is often associated with cognitive disability. CMT1 and CMT2 are primarily autosominal dominant, while CMT4 is autosomal recessive.
The most common type is CMT1, accounting for nearly half of cases, and the most frequent gene mutation causing CMT1 is PMP22 which encodes for peripheral myelin protein 22. Diagnosis is often made based on a combination of family history, EMG, genetic studies, and clinical characteristics which, in addition to neuropathy, include pes cavus, bilateral foot drop, and a tapering appearance of the distal limbs due to muscle atrophy. Differential diagnosis for Charcot-Marie Tooth includes hereditary neuropathy with liability to pressure palsies, hereditary neuralgic amyotrophy, and amyloid-associated neuropathies such as transthyretin-associated amyloidosis. Management is mainly symptomatic, including physical therapy, orthotics, pain control, and avoidance of aggravating factors such as obesity.
- Bird TD. Charcot-Marie-Tooth Hereditary Neuropathy Overview. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [online]. Available at http://www.ncbi.nlm.nih.gov/books/NBK1358/. Accessed December 2014.
- Saporta MA. Charcot-Marie-Tooth disease and other related neuropathies. Continuum 2014; 20: 1208-1225.
Submitted by Sarah Wesley MD, Department of Neurology, Mount Sinai Beth Israel Medical Center.
Disclosures: Dr. Wesley is a member of the Residents & Fellows Section of Neurology.