A new MPZ mutation associated with a mild CMT1 phenotype presenting with recurrent nerve compression.
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.
Magot
Armelle
A
Centre de Référence Maladies Neuromusculaires de l'Enfant et de l'Adulte Nantes-Angers, Hôtel Dieu 44093, Nantes Cedex, France. armelle.magot@univ-nantes.fr
Latour
Philippe
P
Mussini
Jean-Marie
JM
Mourtada
Reda
R
Guiheneuc
Pierre
P
Pereon
Yann
Y
D000328:Adult; D002607:Charcot-Marie-Tooth Disease / Q000150:complications / Q000235:genetics*; D018388:Codon, Terminator / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods; D005091:Exons; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D018993:Myelin P0 Protein / Q000235:genetics*; D009408:Nerve Compression Syndromes / Q000209:etiology / Q000235:genetics*; D009431:Neural Conduction / Q000502:physiology; D010641:Phenotype; D014443:Tyrosine / Q000235:genetics
D018388:Codon, Terminator; D018993:Myelin P0 Protein; D014443:Tyrosine