[Application of inter-fluorescence in situ hybridization of chromosome 13/21 alpha satellite probe in amniotic cells for prenatal diagnosis trisomy 21 syndrome].

OBJECTIVE

To investigate the prenatal diagnosis of trisomy 21 syndrome using chromosome 13/21 alpha satellite probe fluorescence in situ hybridization (FISH) on uncultured interphase cells from amniotic fluid.

METHODS

The interphase amniocytes of 10 fetuses who were detected normal and 3 fetus who were detected trisomy by prenatal cytogenetic diagnosis were selected. We did FISH which used chromosome 13/21 alpha satellite probe directly on the uncultured amniocytes of these 13 samples.

RESULTS

The total rate of the hybridization was 36.7% and 38.6% in control group and observation group respectively, showed no significantly difference. There were four signals in the nucleus, two groups were 36.5% and 3.9% respectively, there were five signals in the nucleus, two groups were 4.0% and 36.1% respectively. The control group and observation group showed significantly difference by the statistical chi 2 values (P < 0.01). Trisomy 21 syndrome was diagnosed when nucleus of five signals accounted for more than 36.1%.

CONCLUSION

FISH with Chromosome 13/21 alpha satellite probe is a valuable method for rapid prenatal diagnosis of trisomy 21 syndrome.