Phenotypic heterogeneity in hereditary neuropathy with liability to pressure palsies associated with chromosome 17p11.2-12 deletion.
Hereditary neuropathy with liability to pressure palsies (HNPP) is commonly associated with a 1.5-megabase deletion on chromosome 17p11.2-12. We analyzed the phenotypic expression of the deletion in 39 HNPP patients from 16 families carrying the deletion. Two-thirds of the individuals had episodes of acute mononeuropathy, often involving nerve territories of the upper limbs or brachial plexus; however, 41% of affected subjects were unaware of their disease, and 25% were almost or totally free of symptoms; one-third complained of chronic symptoms and four older patients had a picture of polyneuropathy. Electrophysiologic abnormalities differed among affected subjects, ranging from conduction abnormalities localized at common entrapment sites to diffuse conduction slowing, usually more evident at entrapment sites; patients from one family had preeminent proximal involvement. The spectrum of phenotypic expression of deletion-associated HNPP appears to be broader than previously thought. The prevalence of the disease is probably underestimated, and the availability of molecular diagnosis should increase disease detection.
Pareyson
D
D
Department of Neurology, Instituto Nazionale Neurologico C. Besta, Milan, Italy.
Scaioli
V
V
Taroni
F
F
Botti
S
S
Lorenzetti
D
D
Solari
A
A
Ciano
C
C
Sghirlanzoni
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D002886:Chromosomes, Human, Pair 17; D004594:Electrophysiology; D005260:Female; D017353:Gene Deletion; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D010243:Paralysis / Q000235:genetics*; D010641:Phenotype; D011312:Pressure