Normal expression of myelin protein zero with frame-shift mutation correlates wi

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J Peripher Nerv Syst. 2006 Mar;11(1):61-6.

Normal expression of myelin protein zero with frame-shift mutation

correlates with mild phenotype.

Steck AJ, Erne B, Pareyson D, Sghirlanzoni A, Taroni F, Schaeren-

Wiemers N.

Departments of Research and Neurology, University Hospital Basel,

Pharmacenter, Basel, Switzerland.

Abstract Mutations in the gene encoding for myelin protein zero (MPZ)

cause inherited demyelinating peripheral neuropathies of different

severity. The molecular and cellular mechanisms by which the MPZ

mutations cause neuropathy are incompletely understood.

We investigated MPZ, myelin basic protein, and peripheral myelin

protein 22 (PMP22) protein expression levels in a nerve biopsy of a

Charcot-Marie-Tooth type 1B patient heterozygous for the Val 102

frame-shift mutation.

We demonstrate by quantitative immunohistochemical as well as by

Western blot analyses that MPZ expression levels were not reduced in

myelin membranes, a finding that is in accordance with the mild

phenotype of this patient. Our data show that heterozygous 'loss-of-

function' of MPZ may not necessarily lead to reduced protein levels.

In conclusion, we demonstrate that careful analysis of protein

expression levels in peripheral nerve tissues provides important

information with respect to the understanding of the molecular basis

of these neuropathies.