Charcot-Marie-Tooth Neuropathy Type 2 – RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY

Excerpt

NOTE: THIS PUBLICATION HAS BEEN RETIRED. THIS ARCHIVAL VERSION IS FOR HISTORICAL REFERENCE ONLY, AND THE INFORMATION MAY BE OUT OF DATE.

Clinical characteristics: Charcot-Marie-Tooth hereditary neuropathy type 2 (CMT2) is an axonal (non-demyelinating) peripheral neuropathy characterized by distal muscle weakness and atrophy, mild sensory loss, and normal or near-normal nerve conduction velocities. CMT2 is clinically similar to CMT1, although typically less severe. Peripheral nerves are not enlarged or hypertrophic. The subtypes of CMT2 are similar clinically and distinguished only by molecular genetic findings.

Diagnosis/testing: The diagnosis is based on clinical and EMG/NCV findings, and in many instances by identification of diagnostic changes in one of the genes that determine the CMT2 subtypes.

Management: Treatment of manifestations: Treatment by a team including a neurologist, physiatrists, orthopedic surgeons, physical, and occupational therapist; special shoes and/or ankle/foot orthoses (AFO) to correct foot drop and aid walking; surgery as needed for severe pes cavus; forearm crutches, canes, wheelchairs as needed for mobility; exercise as tolerated; symptomatic treatment of pain, depression, sleep apnea, restless legs syndrome.

Prevention of secondary complications: Daily heel cord stretching to prevent Achilles' tendon shortening.

Surveillance: Monitoring gait and condition of feet to determine need for bracing, special shoes, surgery.

Agents/circumstances to avoid: Obesity, which makes ambulation more difficult; medications known to cause nerve damage (e.g., vincristine, isoniazid, nitrofurantoin).

Other: Career and employment counseling.

Genetic counseling: Most subtypes of CMT2 are inherited in an autosomal dominant manner; however, some are inherited in an autosomal recessive manner. Most probands with an autosomal dominant CMT2 subtype have inherited the pathogenic variant from an affected parent. The offspring of an individual with autosomal dominant CMT2 are at a 50% risk of inheriting the pathogenic variant.