Charcot-Marie-Tooth Disease

Incidence: 1:2500 people

Peripheral disease severity varying from mild to severe autonomic, motor and sensory neuropathy

Potential for postop weakness, especially following nondepolarizing neuromuscular blocking agents

Resp insufficiency secondary to diaphragmatic or phrenic nerve dysfunction

Preexisting vocal cord palsy or paralysis

Secondary nerve entrapments or injuries with intraop positioning

Peripheral neuropathy is caused by peripheral demyelination (altered myelin function or production) or axonal loss (altered axonal structure or function).

Neuropathies can be autonomic, motor, sensory, or mixed.

Distal weakness and sensory loss typically develop in the first 2 decades of life, followed by a slowing in disease progression with resultant skeletal deformities (more commonly in feet) and loss of DTRs.

Most pts remain ambulatory with a normal life span, but quality of life is often affected.

CMT is diagnosed by electrophysiologic and molecular genetic testing, occasional muscle biopsy.

Management of the disease process is often multidisciplinary and should include neurologists, physical therapists, orthopedists, and geneticists, among others.

Surgery aims to preserve or improve quality of life and functional independence.

Most common hereditary, peripheral, motor, and sensory neuropathy

• Also known as HMSN

• Over 70 genes identified with at least one CMT phenotype

• Autosomal dominant and X-linked dominant inheritance more common

Inheritance: Wide range of genetic heterogeneity

• Majority of types are autosomal dominant (CMT1 and CMT2)

• Over 20% of pts without known familial Hx for CMT

• X-linked recessive and autosomal recessive less common

Main subtypes

• Type 1 (CMT1): Demyelinating (altered myelin function/production); autosomal dominant; slow nerve-conduction velocity; most predominant form in Western countries (in those of European descent)

• Type 2 (CMT2): Axonal loss (altered axonal structure/function); autosomal dominant; preserved nerve-conduction velocity

• Type 3 (CMT3): Severe early onset (Dejerine-Sottas disease)

• Type 4 (CMT4): Demyelinating or axonal loss; autosomal recessive

• X-linked CMT (CMTX)