Comparison of different techniques for detecting 17p12 duplication in CMT1A.

Charcot-Marie-Tooth type 1A is caused by a 1.5Mb DNA duplication in the 17p12 chromosomal region encompassing the peripheral myelin protein 22 gene. In the present study, we compared the Real-Time PCR with the other methods currently used for the diagnosis of Charcot-Marie-Tooth. By using a combination of junction fragment PCR, analysis of microsatellite markers, and pulsed field gel electrophoresis, we identified 76 unrelated patients with 17p12 duplication. In these patients, junction fragment PCR detected 63% of cases of duplication, the microsatellite markers method revealed 74%, while the combined use of microsatellite markers and junction fragment PCR revealed 91% of cases of Charcot-Marie-Tooth type 1A. Pulsed field gel electrophoresis detected 100% of the cases with duplication, even in presence of atypical 17p12 duplication. Real-Time PCR detected 100% of the cases with Charcot-Marie-Tooth type 1A and was comparable to pulsed field gel electrophoresis. However, in contrast to pulsed field gel electrophoresis, Real-Time PCR does not need fresh blood, minimizes diagnosis time and cost, and thus can be easily used for the molecular diagnosis of Charcot-Marie-Tooth type 1A.