[Application of real-time fluorescence quantitative polymerase chain reaction techniques for prenatal diagnosis of Down syndrome].

Objective: To investigate the value of real-time fluorescence quantitative PCR in diagnosis of Down syndrome with uncultured amniotic cells.
Methods: The uncultured amniocytes of 80 fetuses who were confirmed disomy 21 by chromosome analysis and 5 fetuses detected trisomy 21 and peripheral blood samples of 7 children diagnosed as Down syndrome were collected to extract gDNA and the real-time fluorescence quantitative PCR method was used to detect the original copies of Down syndrome critical region gene(3) (DSCR(3)) and GAPDH gene and then the ratio of DSCR(3)/GAPDH was calculated.
Results: The PCR product ratios of DSCR(3) to GAPDH in trisomy 21 from amniocytes and peripheral blood were ranged from 1.64 to 1.98 while in the normal control the ratio was only from 0.46 to 1.30.
Conclusion: Real-time fluorescence quantitative PCR is a valuable method for rapid and accurate prenatal diagnosis of Down syndrome in uncultured amniotic cells.