CMT 1A and HNPP: A rapid and reliable detection system for the analysis of PMP22

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J Hum Genet. 2006 Feb 4

A rapid and reliable detection system for the analysis of PMP22 gene

dosage by MP/DHPLC assay.

Lin CY, Su YN, Lee CN, Hung CC, Cheng WF, Lin WL, Chen CA, Hsieh ST.

Institute of Biomedical Engineering, National Taiwan University,

Taipei, Taiwan.

Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy

with liability to pressure palsies (HNPP) are caused by a 1.5-Mb

duplication and a deletion at chromosome 17p11.2-12 encompassing the

peripheral myelin protein 22 gene (PMP22), respectively. We developed

a rapid and reliable detection system for duplications/deletions of

the PMP22 gene based on measurement of gene copy number. The method

involves amplification of a test locus with unknown copy number and a

reference locus of known copy number by multiplex PCR (MP), followed

by denaturing high-performance liquid chromatography (DHPLC) or

capillary electrophoresis detection to identify single copy changes.

Thirty-two patients with CMT1A, 17 patients with HNPP, and 61

unaffected individuals were analyzed. Using the same competitive MP

protocol, the measured PMP22 gene dosage revealed concordant results

between DHPLC and capillary electrophoresis analysis. The results of

the MP/DHPLC or the MP/capillary electrophoresis assay were all

confirmed by PCR-restriction fragment length polymorphism analysis.

We concluded that the MP/DHPLC assay is an efficient, accurate, and

reliable technique for gene dosage determination of the PMP22 gene

for CMT1A duplication and HNPP deletion. This technique further

extends the application of DHPLC as an alternative method for the

measurement of gene amplifications and heterozygous deletions in

different genetic diseases.