OBJECTIVE: A new method in prenatal diagnostics allows to demonstrate certain numeric chromosomal aneuploidies in amniotic cells within 24 h in contrast to conventional methods which take 1-3 weeks. MATERIALS: The experience with this rapid fluorescence in situ hybridization (FISH) method is compared to standard karyotyping and its clinical relevance is described in a large clinical pilot study. FISH on uncultured amniocytes has been 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. RESULTS: FISH was performed successfully in 3,150 prenatal cases. All trisomies 13, 18 and 21 and all cases with gonosomal aberrations were detected by FISH 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 chromosomal aneuploidies.
OBJECTIVE: A new method in prenatal diagnostics allows to demonstrate certain numeric chromosomal aneuploidies in amniotic cells within 24 h in contrast to conventional methods which take 1-3 weeks. MATERIALS: The experience with this rapid fluorescence in situ hybridization (FISH) method is compared to standard karyotyping and its clinical relevance is described in a large clinical pilot study. FISH on uncultured amniocytes has been 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. RESULTS: FISH was performed successfully in 3,150 prenatal cases. All trisomies 13, 18 and 21 and all cases with gonosomal aberrations were detected by FISH 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 chromosomal aneuploidies.