What are the motor symptoms and signs of Charcot-Marie-Tooth (CMT) disease?

Updated: Feb 19, 2019
  • Author: Francisco de Assis Aquino Gondim, MD, PhD, MSc, FAAN; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Motor symptoms usually predominate over sensory symptoms. Motor and sensory symptoms may be exclusive in the subgroup of hereditary motor neuropathies (HMN) and hereditary sensory neuropathies (HSN), respectively, which are not discussed in this article.

Proximal weakness is rarely present except in the most severely affected patients, in some unusual pedigrees, and with brachial plexus neuropathies, which means that even patients with marked weakness are able to walk. Manipulating small objects such as zippers, forks, or pencils may be difficult because of motor and sensory impairment. On examination, most patients with CMT exhibit distally dominant weakness, hyporeflexia, and muscle atrophy affecting the legs earlier and more significantly than the arms.

Patients report loss of balance, tripping over objects because of foot-drop and impaired sensation, weakness, and foot deformities resulting in unequal wearing of shoes and trouble finding shoes that fit. Foot deformities include pes cavus, high arches or flat feet, hammertoes, and shortened Achilles tendons. Such deformities become more prevalent with age but are variable even among relatives of the same age. Wasting of foot and distal lower extremity muscles develops over time and may produce the classic "inverted champagne bottle" appearance. Some patients with CMT, and in particular patients with HNPP, find that wider shoes are more comfortable because of high arches and hammertoes or because local nerve compression may be less (in the case of HNPP).

Families with CMT and pyramidal features have also been reported. In 2003, Vucic et al found 2 families with dominantly inherited axonal neuropathies, distal wasting, weakness, pes cavus, sensory loss, and mild pyramidal signs (including extensor plantar responses, mild increase in tone, and preserved or increased reflexes but no spastic gait). [13] Linkage studies excluded Charcot-Marie-Tooth disease type 2A (CMT2A), Charcot-Marie-Tooth disease type 2B (CMT2B), Charcot-Marie-Tooth disease type 2D (CMT2D), Charcot-Marie-Tooth disease type 2E (CMT2E), CMT2, amyotrophic lateral sclerosis 4 (ALS4), hereditary motor neuropathy type 2 (HMN II) and mutations in the PMP22, MPZ/Po, or EGR2 genes.

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