Prenatal Diagnostics on Uncultured Amniocytes

Fluorescence in situ hybridization (FISH) in prenatal diagnostics permits the demonstration of certain numeric chromosomal aneuploidies in amniotic cells within 24h, in contrast to conventional methods, which take 1–3 weeks. The experience of using this FISH method has been compared to standard karyotyping. FISH on uncultured amniocytes was performed from 12 weeks of gestation to the third trimester using commercially available chromosome-specific DNA probes for chromosomes 13, 18, 21, X and Y. FISH was performed successfully in nearly 10,000 prenatal cases. All of the trisomies 13, 18 and 21 and all cases with gonosomal aberrations were detected by FISH analysis. No false-positive results were obtained using FISH. For all analyzable disorders, the FISH results were in complete agreement with standard cytogenetics. In our experience, FISH is a valuable and reliable method for the rapid diagnosis of numeric chromosomal aneuploidies (Quick Test).