ABSTRACT
By detecting SRY gene of cell-free fetal DNA ( cffDNA) in maternal peripheral blood, the sex of fetuses was determined, the risks of sex-linked genetic disorders were assessed and the birth rate of sick fetuses was decreased. A method of real-time polymerase chain reaction ( PCR) coupled with invader assay was established to detect SRY gene. This method possessed the advantages such as high sensitivity, high specificity and non-contaminated with closed tube detection. Under the optimized reaction conditions such as 250 nmol/L detection probes, 7. 5 U FEN1 enzyme, 0. 5 U Taq polymerase and 67℃ of annealing temperature in pre-amplification, the simulated samples as low as 4% ( 4 copies/μL ) were detected and two clinical samples with the gestation age of 9 weeks and 10 weeks were successfully detected. The detection results showed 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.
ABSTRACT
By detecting SRY gene of cell-free fetal DNA ( cffDNA) in maternal peripheral blood, the sex of fetuses was determined, the risks of sex-linked genetic disorders were assessed and the birth rate of sick fetuses was decreased. A method of real-time polymerase chain reaction ( PCR) coupled with invader assay was established to detect SRY gene. This method possessed the advantages such as high sensitivity, high specificity and non-contaminated with closed tube detection. Under the optimized reaction conditions such as 250 nmol/L detection probes, 7. 5 U FEN1 enzyme, 0. 5 U Taq polymerase and 67℃ of annealing temperature in pre-amplification, the simulated samples as low as 4% ( 4 copies/μL ) were detected and two clinical samples with the gestation age of 9 weeks and 10 weeks were successfully detected. The detection results showed 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.
ABSTRACT
A method for the real-time polymerase chain reaction ( PCR ) coupled with high specific invader assay to detect single nucleotide polymorphism ( SNP) was established. To reduce the background signal, the amount of flap endonuclease 1 ( FEN1 enzyme ) and wild-type detection probe was optimized. Under the optimum conditions including 0. 05 μmo/L invasive oligonucleotide probe, 0. 125 μmol/L wild-type detection probe, 0. 5 μmol/L mutation detection probe, 0. 25 μmol/L each fluorescence resonance energy transfer (FRET) probe and 1. 5 U FEN1, the background signal of wild-type sample and mutation sample was dramatically decreased and the background interference to the detecting results was thus eliminated. A total of 21 cases of aldehyde dehydrogenase-2*2 ( ALDH2*2 ) , 19 cases of cytochrome p450 2 C19*2 ( CYP2 C19*2 ) and 19 cases of CYP2C19*3 were analyzed with the established method, and the genotypes of ALDH2*2 were 10 cases of GG homozygote, 8 cases of GA heterozygote and 3 cases of AA homozygote; the genotypes of CYP2C19*2 were 9 cases of GG homozygote, 8 cases of GA heterozygote and 2 cases of AA homozygote;and the genotypes of CYP2C19*3 were 18 cases of GG homozygote and 1 case of GA heterozygote. These results were consistent with those by pyrosequencing. The established method was specific, simple, short time-consuming and low cost, and could be used for the detection of SNP genotyping with non-polluting in single closed tube.