Highly Sensitive and Specific Detection of SRY Gene for Non–invasive Prenatal Diagnosis

Abstract

Abstract Through detecting SRY gene of cell–free fetal DNA (cffDNA) in maternal peripheral blood, the sex of fetuses can be determined, risks of sex–linked genetic disorders can be assessed and birth rate of sick fetuses can be decreased. In this study, a method of real–time polymerase chain reaction (PCR) coupled with invader assay, which was highly sensitive, highly specific and non–contaminated with closed tube detection, was established to detect SRY gene. The optimal reaction conditions were determined to be 250 nM of detection probes, 7.5 U of FEN1 enzyme, 0.5 U of Taq polymerase and 67 °C of annealing temperature in pre–amplification. Finally, it was demonstrated that the simulated samples as low as 4‰ (4 copies μL −1 ) could be detected and two clinical samples with the gestation age of 9 and 10 weeks respectively were also successfully detected. The experimental results indicated that this method could be used to detect SRY gene of cffDNA in maternal peripheral blood, providing an effective technique for clinical non–invasive prenatal diagnosis based on SRY gene.