Prenatal diagnosis of Charcot-Marie-Tooth disease type 1A by interphase fluorescence in situ hybridization

Charcot-Marie-Tooth Disease (CMT) is the most common cause of peripheral ne uropathy, with an incidence of 1:2500 persons affected. Previously, we repo rted the use of fluorescence in situ hybridization (FISH) to detect the com mon submicroscopic duplication of 17p12 found in more than 98 per cent of i ndividuals with CMT1A. We found that FISH is a reliable means for the diagn osis of the duplication of 17p12 in peripheral blood and reported the valid ation of the FISH assay for amniotic fluid specimens. Herein, we report the validation of the FISH assay for use on chorionic villus samples (CVS) to prenatally diagnose CMT1A duplications and the testing of 17 prenatal speci mens. Seven fetuses were found to carry the duplication and are predicted t o be affected. FISH is a rapid assay in prenatal specimens, with a 9.3 day average turn-around time. Limited follow-up on pregnancies indicates that t he duplication found in CMT1A is reliably diagnosed in the fetus, using FIS H on either amniotic fluid specimens or CVS. Copyright (C) 1999 John Wiley & Sons, Ltd.