Hereditary neuropathy with liability to pressure palsies: description of seven patients without known family history.
OBJECTIVE
Hereditary neuropathy with liability to pressure palsies (HNPP) is an inherited disorder resulting in a polyneuropathy with particular involvement at sites of entrapment, and is often underdiagnosed or misdiagnosed. We report findings on seven patients referred for evaluation of focal mononeuropathies or polyneuropathies of undetermined etiology, in whom we established a diagnosis of HNPP.


METHODS
We retrospectively reviewed clinical, electrophysiological and laboratory data for patients diagnosed with HNPP over a 4-year period at our institution.


RESULTS
All patients had transient or recurrent neurological symptoms, some with residual deficits. No patients had a family history of any neuropathy. Electrodiagnostic studies revealed abnormal conduction findings at symptomatic and asymptomatic sites. Testing for the Peripheral Myelin Protein (PMP22) deletion was positive in all patients.


CONCLUSIONS
A high index of clinical suspicion and thorough electrodiagnostic evaluation can lead to correct diagnosis of HNPP, despite the absence of a positive family history.
Beydoun
S R
SR
Department of Neurology, Keck School of Medicine at University of Southern California, Los Angeles, CA, USA. sbeydoun@usc.edu
Sykes
S N
SN
Ganguly
G
G
Lee
T S
TS
D000200:Action Potentials / Q000235:genetics; D000293:Adolescent; D000328:Adult; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D004568:Electrodiagnosis / Q000379:methods; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D005820:Genetic Testing; D005838:Genotype; D020271:Heredodegenerative Disorders, Nervous System / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D009133:Muscular Atrophy / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D009185:Myelin Proteins / Q000235:genetics; D009431:Neural Conduction / Q000235:genetics; D010292:Paresthesia / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D010525:Peripheral Nerves / Q000503:physiopathology*; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies
D005819:Genetic Markers; D009185:Myelin Proteins; C073687:PMP22 protein, human