Histopathological features of X-linked Charcot-Marie-Tooth disease in 8 patients from 6 families with different connexin32 mutations.
J Peripher Nerv Syst. 2001-06-01; 6(2): 79-84
DOI: 10.1046/j.1529-8027.2001.01011.x
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1. J Peripher Nerv Syst. 2001 Jun;6(2):79-84.
Histopathological features of X-linked Charcot-Marie-Tooth disease in 8 patients
from 6 families with different connexin32 mutations.
Vital A(1), Ferrer X, Lagueny A, Vandenberghe A, Latour P, Goizet C, Canron MH,
Louiset P, Petry KG, Vital C.
Author information:
(1)Département de Neuropathologie, Université Victor Ségalen-Bordeaux 2, France.
There is still confusion as to whether X-linked Charcot-Marie-Tooth disease
(CMTX) is primarily an axonal disorder or is primarily demyelinating. Eight
symptomatic patients, 7 males and 1 female, from 6 families with identified
connexin32 mutations underwent a superficial peroneal nerve biopsy. Quantitative
and ultrastructural studies were performed, and histopathological lesions in
these 8 patients proved to be quite homogeneous. The myelinated fiber count was
within normal values or only moderately decreased. In 7 cases, the distribution
of myelinated fibers was unimodal due to a loss of large fibers, coexisting with
numerous clusters of small regenerating fibers. At ultrastructural level, these
clusters were often surrounded by flattened Schwann cell processes giving an
aspect of « pseudo-onion bulb » formation. There was no « naked axon » (ie,
demyelinated axon), and real « onion bulb » formations composed of flattened
Schwann cell processes surrounding an isolated myelinated fiber were discrete and
not numerous. Macrophages laden with myelin debris were scarce or absent in the
endoneurium. Several fibers appeared discretely hypomyelinated and the calculated
g-ratio was scarcely higher than the mean control value. Lesions of unmyelinated
fibers were absent in 7 cases and mild in one. Given that the primary defect
concerns connexin32, we think that the histopathological features observed in our
patients correspond to primary hypomyelination rather than to ongoing
demyelination. The associated axonal degeneration might be secondary to defective
axon-Schwann cell interactions.
DOI: 10.1046/j.1529-8027.2001.01011.x
PMID: 11446387 [Indexed for MEDLINE]