Charcot Marie Tooth Disease. A Single Disorder?
Résumé
Peripheral neuropathies are subdivided into acquired and hereditary transmitted disorders.
Among hereditary peripheral neuropathies, the most frequent is Charcot-Marie-Tooth disease (CMT).
We will describe below, in detail, this disorder and its different forms.
Charcot-Marie-Tooth disease constitutes a clinically and genetically heterogeneous group of
hereditary motor and sensory peripheral neuropathies. On the basis of electrophysiologic properties
and histopathology, CMT has been divided into primary peripheral demyelinating (type 1) and
primary peripheral axonal (type 2) neuropathies. The demyelinating neuropathies classified as CMT
type 1, also known as HMSN I, are characterized by severely reduced motor nerve conduction
velocities (NCV) (less than 38 m/s) and segmental demyelination and remyelination with onion
bulb formations on nerve biopsy. The axonal neuropathies classified as CMT type 2, also known as
HMSN II, are characterized by normal or mildly reduced NCVs and chronic axonal degeneration and
regeneration on nerve biopsy. Among the CMT1 group, there are X-linked, autosomal dominant and
autosomal recessive forms of CMT.
The typical presenting symptom is a weakness of the feet and ankles. The initial physical findings
are depressed or absent tendon reflexes with a weakness of foot dorsiflexion at the ankle. The typical
affected adult has a bilateral foot drop, symmetrical atrophy of muscles below the knee (stork leg
appearance), pes cavus, atrophy of intrinsic hand muscles, especially the thenar muscles of the thumb,
and absent tendon reflexes in both upper and lower extremities. The life span is not decreased
Domaines
Sciences du Vivant [q-bio]
Origine : Publication financée par une institution
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