research differences in Type 1 and 2

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Abstract from Cir Cir. 2004 Sep;72(5):387-394.

(Recently indexed in the National Library of Medicine)

Peripheral hereditary neuropathies: Charcot-Marie-Tooth types 1 and 2

Villegas-Castrejon H, Solis-Arrieta L, ez- F, Escobar-

Cedillo RE, - BE.

Departamento de Morfologia Celular y Molecular, Torre de

Investigacion, Piso 0, Calz. Mexico-Xochimilco 289, Col. Arenal de

Guadalupe, 14389 Mexico D.F., Mexico.

Objective: We report 14 cases of patients with Charcot-Marie-Tooth

types 1 (CMT) and type 2 (CMT2). The objective of this study was to

determine the diagnostic value of structural studies of peripheral

nerve and striated muscle biopsies and to discuss correlations with

clinical symptoms and electrophysiologic findings. Material and

methods: Nerve and muscle biopsies were obtained and processed

according to standards methods for transmission electron microscopy.

Diagnosis of CMT was based on clinical electrophysiologic findings.

Results: Our results demonstrated that myelinated fibers showed

moderate-to- severe demyelinization and remyelinization, folding

complex, tomacula formations, and presence of moderate vacuoles into

myelin. The axonal cytoskeleton shows an important decrease of

neurofilaments and microtubules in myelinated and unmyelinated

nerves. Striated muscle showed different degenerative changes in Z

disc. One important finding was presence of crystals inclusions in

mitochondrion. In 11 cases, it was possible to find relevant changes

in mitochondria-like hyperplasia. In this study, we had four cases

with > 20 years of evolution; these cases showed relevant

degenerative changes in nerve and muscle. Nerves presented great

demyelination with damage in cytoskeleton of the axon, while fibers

of muscle had necrosis and hyalinization.

Conclusions: According to our results, it is possible to distinguish

morphologically CMT subtypes, due to the fact that in CMT2 we found a

50% decrease of filaments and microtubules that were reduced in

myelinic axons; this finding does not occur in CMT1.