Process for the preparation of DNA primers and probes for minimally invasive prenatal PCR diagnosis of Trisomy 21 chromosome in the fetus ON blood of pregnant women, kits comprising primers and probes derived in accordance with this method, and minimally invasive diagnostic method that uses said primers AND PROBES

摘要

1. A method of obtaining DNA primers and probes for minimally invasive prenatal PCR diagnosis of trisomy of the 21st chromosome in the fetus by the blood of a pregnant woman, which uses: (a) site-specific restriction endonuclease (s), sensitive ( -th) for methylation, (b) a sample of human hypermethylated or fetal DNA, (c) a sample of hypomethylated or adult human DNA, characterized in that it comprises the following steps: (1) select a site for differential methylation of fetal DNA of the 21st chromosome and DNA of the 21st chromosome adult s sensitive to said endonuclease (s), (2) synthesize the forward and reverse primers corresponding to an amplicon from 60 to 300 pairs of nucleotides in length containing the differential methylation site (s) of the 21st chromosome, as well as a probe corresponding to this amplicon, (3) carry out the polymerase chain reaction of a mixture of samples (b) and (c) after their treatment with restriction endonuclease (a), at least at three different concentration ratios of these samples, (4) pairs of primers and probes are selected to ensure efficiency reaction and PCR above 90% and linearity when changing the relative concentration of samples (b) and (c) above 0.9.2. A kit for minimally invasive prenatal PCR diagnosis of trisomy of the 21st chromosome in the fetus by the blood of a pregnant woman, containing at least one pair consisting of direct and reverse primers obtained in accordance with the method of claim 1, and at least , one probe corresponding to them. 3. A kit according to claim 2, characterized in that the amplicon size is an integer in the range from 60 to 300 nucleotide pairs, preferably an integer in the range