Although the electrophysiological data was consistent with HNPP, the patient denied family history of neuropathies and, gene analysis did not reveal deletion on chromosome 17pll.2-12.
Spectrum of clinical and electrophysiologic features in HNPP patients with the 17pll.2 deletion.
Patients with HNPP were diagnosed by clinical, electrophysiological and nerve biopsy findings.
Twelve sural nerve biopsies with hereditary neuropathy with liability to pressure palsy (HNPP) were included in the study
We tried to evaluate this new polymorphic system for diagnostic testing of HNPP. HNPP patients are hemizygous for the region duplicated in CMT1A patients.
Estimation of the mutation frequencies in Charcot-Marie-Tooth disease type 1 (CMT1) and hereditary neuropathy with liability to pressure palsies (HNPP): a European collaborative study.
Several methods have been used in clinical laboratories for the molecular diagnosis of CMT1A and HNPP (10).
PCR-based data of HNPP deletions are typically less robust because they do not allow direct detection of the deletion, but only infer the deletion by detecting a single allele for any marker tested.
CMT1A is associated with a tandem DNA duplication of a specific 1.5-Mb region at chromosome 17p11.2-p12 (1, 2), whereas HNPP
is associated with a deletion of the same region (3).
The PMP22/NF1 ratios for CMT1A, unaffected, and HNPP
samples were ~1.5, 1.0, and 0.5, respectively.
Molecular diagnosis of CMT1A or HNPP
involves the detection of the respective DNA duplication or deletion.
Locations of crossover breakpoints within the CMT1A-REP repeat in Japanese patients with CMT1A and HNPP
. Hum Genet 1997;99:151-4.