Detection of aneuploidy involving chromosomes 13, 18, or 21, by fluorescence in situ hybridization (FISH) to interphase and metaphase amniocytes.

Fluorescence in situ hybridization (FISH) with chromosome-specific probes has been applied to detection of numerical aberrations involving chromosomes 13, 18, and 21 in metaphase and interphase amniocytes. High-complexity, composite probes for chromosomes 13, 18, and 21 were used as hybridization probes for this study. These probes were constructed as chromosome-specific libraries in Bluescribe plasmids and are designated pBS-13, pBS-18, and pBS-21. Elements of these probes bind at numerous sites along the target chromosome and, when detected fluorescently, stain essentially the entire long arm of the target chromosome. The target chromosome number (i.e., the number of chromosomes of the type for which the probe was specific) was correctly determined in 20 of 20 samples in which metaphase spreads were analyzed and in 43 of 43 samples in which interphase nuclei were analyzed; all of these studies were conducted in blind fashion. These results suggest the utility of FISH with composite probes for rapid detection of numerical aberrations in metaphase and interphase amniotic cells.