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

Updated: Jun 23, 2021
  • Author: Divakara Kedlaya, MBBS; Chief Editor: Elizabeth A Moberg-Wolff, MD  more...
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Nerve biopsy rarely is indicated for the diagnosis of Charcot-Marie-Tooth disease (CMT), especially because genetic testing is available. Biopsies sometimes are performed in cases of diagnostic dilemmas. Findings vary in different types of CMT, as follows:

  • In CMT-1, peripheral nerves contain few myelinated fibers, and intramuscular nerves are surrounded by rich connective tissue and hyperplastic neurilemma. Lengths of myelin are atrophic along the fibers. Concentric hypertrophy of the lamellar sheaths is seen. Onion bulb formation, made up of circumferentially directed Schwann cells and their processes, frequently is observed.

  • In CMT-2, axon loss with wallerian degeneration generally is found.

  • In CMT-3, or Dejerine-Sottas disease, demyelination with thinning of the myelin sheath is observed.

  • Inflammatory infiltrate, indicating an autoimmune demyelinating process, should not be present.

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