Hereditary Neuropathy with liability to Pressure Palsies (HNPP. tomaculous neuropathy) is an autosomal dominant disorder characten/cd by recurrent focal neuropathies. It is associated with a deletion on chromosome 17pll.2. encompassing the Peripheral Myelin Protein-22 (PMP22) gene. Our scries include now 72 HNPP patients carrying the deletion from 41 families. We observed remarkable heterogeneity of phcnolypic expression not only in clinical, but also in electrophysiologic and even neuropathologic findings. Age at onset ranged between 8 and 64 years. Episodes of painless acute neuropathy, reported by 61% of patients, often involved the brachial plexus (35%). Six older patients presented with polyncuropathy. On the other hand. 26% of subjects had normal neurologic examination. Conduction slowing across common entrapment sites was the most frequent electrophysiologic finding (87%). Nerve conduction velocities ranged from normal to considerably slowed, usually asymmetrically and in a nonhomogeneous fashion. A few patients had preeminent proximal conduction slowing. Although numerous typical tomacula allowed the neuropathologic diagnosis in 11 cases, in two cases they were so scanty that the diagnosis of HNPP could be confirmed only by genetic findings. We did not found the deletion in two HNPP index cases (and five affected relatives) with typical clinical, electrophysiological and morphological features. The two patients carried two different mutations in the PMP22 gene, both predicted to produce a premature termination of the protein.
|Number of pages||1|
|Journal||Italian Journal of Neurological Sciences|
|Publication status||Published - 1997|
ASJC Scopus subject areas
- Clinical Neurology