Rapid prenatal diagnosis of aneuploidies in uncultured amniocytes by fluorescence in situ hybridization - Evaluation of > 3,000 cases

Objective: A new method in prenatal diagnostics allows to demonstrate certa in numeric chromosomal aneuploidies in amniotic cells within 24 h in contra st to conventional methods which take 1-3 weeks. Materials: The experience with this rapid fluorescence in situ hybridization (FISH) method is compare d to standard karyotyping and its clinical relevance is described in a larg e clinical pilot study. FISH on uncultured amniocytes has been performed fr om 12 weeks of gestation to the third trimester using commercially availabl e chromosome-specific DNA probes for chromosomes 13, 18, 21, X and Y. Resul ts: FISH was performed successfully in 3,150 prenatal cases. All trisomies 13, 18 and 21 and all cases with gonosomal aberrations were detected by FIS H analysis. Neither false-positive nor false-negative results were obtained using FISH. For all analyzable disorders the FISH results were in complete agreement with standard cytogenetics. Conclusions: In our experience, FISH is a valuable and reliable method for rapid diagnosis of numeric chromosom al aneuploidies.