Simultaneous identification of chromosomes 18, X and Y in uncultured amniocytes by using multi-primed in situ labelling technique.

The aim of this study is to validate the multi-PRINS (primed in situ labelling) technique for simultaneous detection of chromosomes 18, X and Y in uncultured amniocytes for prenatal diagnosis of aneuploidy. The sites of the newly synthesized DNA sequences were showed as fluorescent signals by using immunochemistry. A multi-PRINS technique was specifically performed for simultaneous detection in the same cells of three chromosome targets, e.g. chromosomes 18, X and Y. Fluorescent signals corresponding to chromosomes 18, X and Y were showed as yellow, red and green colour spots, respectively. A multi-FISH technique using chromosome 18, X and Y probes was performed for comparison. Sixty cases were analysed using both multi-PRINS and multi-FISH. Fifty to two hundred nuclei were scored for each case for each technique. In all cases, there was no significant difference in the detection of chromosomes 18, X and Y regarding the sensitivity, the specificity and the efficiency; multi-PRINS and multi-FISH yield a similar distribution of the number of spots per nucleus. Both techniques were able to identify aneuploid cases without any ambiguity. Both multi-PRINS and multi-FISH can accurately and reliably detect aneuploidies involving chromosomes 18, X and Y in uncultured amniocytes. Finally, multi-PRINS represents a faster and more cost-effective alternative to FISH for prenatal testing of aneuploidy in uncultured amniocytes.