Charcot-Marie-Tooth (CMT) disease type 2
Incidence
See CMT1. The chromosome involved is at 1p35- p36.
Clinical Characteristics
Charcot-Marie-Tooth (CMT) disease, also known as "peroneal muscular atrophy," is characterized by a progressive muscular atrophy with initial involvement of feet and legs. Symptoms start in the first or second decade of life. Muscle weakness is usually detected as an abnormality of gait (typically steppage or equine gait) or clumsiness in running. Cramps are frequently reported. Physical examination often reveals foot deformities, including pes cavus or equinovarus, and an "inverted champagne bottle" appearance of lower limbs. Deep tendon reflexes are usually absent. Sensory symptoms are very mild, and the patients report them as diminished sensation over the feet. This results in calluses, and less often ulcers, which develop over pressure points. Later in life, patients may experience weakness of intrinsic hand muscle, which may lead to a "claw hand" appearance. Both interfamilial and intrafamilial variability of phenotypic expression has been described in CMT. Electrophysiology represents an important diagnostic tool for CMT disease. On the basis of the electrophysiological data, CMT patients can be divided into two major categories: CMT type 1 disease (CMT1) patients showing decreased motor-nerve conduction velocity (MNCV) and CMT2 patients with normal MNCV.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
Electrophysiology represents an important diagnostic tool for CMT disease. On the basis of the electrophysiological data, CMT patients can be divided into two major categories: CMT type 1 disease (CMT1) patients showing decreased motor-nerve conduction velocity (MNCV) and CMT2 patients with normal MNCV.