A new single-nucleotide deletion of PMP22 in an HNPP family without recurrent pa

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Muscle Nerve. 2008 Jul 18.

A new single-nucleotide deletion of PMP22 in an HNPP family without

recurrent palsies.

Luigetti M, Conte A, Madia F, Mereu ML, Zollino M, Marangi G, Pomponi

MG, Liberatore G, Tonali PA, Sabatelli M.

Istituto di Neurologia, Università Cattolica del Sacro Cuore,

Pol. " A. Gemelli " Largo Gemelli 8, 00168 Rome, Italy.

In this study we describe four patients from the same kindred who

were affected by an autosomal-dominantly inherited peripheral

neuropathy. They presented an unusual combination of clinical,

electrophysiological, and pathological findings in association with a

new mutation of the PMP22 gene.

Clinically, three patients had carpal tunnel syndrome symptoms and

one patient had late-onset peroneal atrophy. Motor and sensory nerve

conduction velocities were reduced without focal slowing at

entrapment sites. Nerve biopsy disclosed diffuse hypomyelination with

focal thickening of the myelin sheath in some fibers.

Sequence analysis of the PMP22 gene showed a single-nucleotide

deletion (227delG) in the affected patients. This mutation, which has

not been reported previously, leads to an open reading frame shift

and probably to a truncated and unstable PMP22 protein.

We conclude that this novel 227delG mutation of PMP22 gives a mild

form of hereditary neuropathy with liability to pressure palsy with

atypical clinical and electrophysiological findings.