Charcot-Marie-Tooth disease (CMT) is the most common cause of peripheral neuropathy, with an incidence of 1: 2500 persons affected. CMT1A is caused by a submicroscopic duplication in 17p12. Several methods exist for determining a diagnosis in an individual. Many of these methods are not suitable for prenatal diagnosis. Previously, we reported the use of fluorescence in situ hybridization (FISH) to detect the common duplication found in more than 98% of individuals with CMT1A. We also have reported the validation of the FISH assay for amniotic fluid specimens and chorionic villus samples. Herein, we report our experience with testing for CMT1A in prenatal specimens.