A new MPZ mutation associated with a mild CMT1 phenotype presenting with recurre

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Muscle Nerve. 2008 Jul 28;38(2):1055-1059.

A new MPZ mutation associated with a mild CMT1 phenotype presenting

with recurrent nerve compression.

Magot A, Latour P, Mussini JM, Mourtada R, Guiheneuc P, Pereon Y.

Centre de Référence Maladies Neuromusculaires de l'Enfant et de

l'Adulte Nantes-Angers, Hôtel Dieu 44093, Nantes Cedex, France.

P0 is a transmembrane protein of the immunoglobulin superfamily that

plays a role in myelin structure and function. Myelin protein zero

gene (MPZ) mutations usually cause a demyelinating variant of Charcot-

Marie-Tooth disease type 1B (CMT1B), but there is a wide spectrum of

phenotypic manifestation of these mutations.

We describe three patients from one family and one separate patient

who presented with a demyelinating neuropathy. Some had recurrent

lesions at compression sites mimicking hereditary neuropathy with

liability to pressure palsies (HNPP). A heterozygous nonsense

mutation (Tyr145Stop) corresponding to a T-to-A transition at

nucleotide position 435 in exon 3 of the MPZ gene was identified in

all patients.

This mutation leads to an extracellular truncated protein, which may

explain the mild phenotype. Therefore, such MPZ gene mutations should

be searched for in cases of demyelinating neuropathy with acute nerve

compression as well as in cases of the HNPP phenotype associated with

normal the PMP22 gene.