Nucleic acid-based tests for RhD typing, gender determination and nucleic acid quantification
The invention in part provides nucleic acid-based assays, which are particularly useful for non-invasive prenatal testing. The invention in part provides compositions and methods for RhD typing, detecting the presence of fetal nucleic in a sample, determining the relative amount of fetal nucleic acid in a sample and determining the sex of a fetus, wherein each of the assays may be performed alone or in combination.
1. A method for determining the relative amount of fetal nucleic acid in a maternal plasma sample, comprising:
(a) amplifying at least 10 polymorphic sites in nucleic acid obtained from a maternal plasma sample, which polymorphic sites comprise single nucleotide polymorphisms with a minor allele frequency of greater than 0.3 and are selected from the group consisting of: rs7551188, rs11247894, rs6687785, rs4487973, rs4648888, rs12089156, rs2050927, rs12125888, rs12143315, rs213624, rs660279, rs635364, rs9431593, rs11166512, rs4329520, rs454782, rs12136370, rs12759642, rs11184494, rs2454175, rs156988, rs10793675, rs1829309, rs1452628, rs4570430, rs12062414, rs7545381, rs6427673, rs10802761, rs642449, rs4839419, rs9324198, rs1192619, rs4657868, rs6426873, rs438981, rs3128688, rs4987351, rs6692911, rs6684679, rs4320829, rs4658481, rs3768458, rs860954, rs10453878, rs10753912, rs1637944 and rs4839282;
(b) quantifying the relative amount of the alleles at said at least 10 polymorphic sites; and
(c) expressing the relative amounts of fetal and maternal alleles as a ratio, wherein the ratio indicates the relative amount of fetal nucleic acid present in the maternal sample.
2. The method of claim 1 , wherein said at least 10 polymorphic sites are selected from the group consisting of rs7551188, rs11247894, rs6687785, rs4487973, rs4648888, rs12089156, rs2050927, rs12125888, rs12143315, rs213624, rs660279, rs635364, rs9431593, rs11166512, rs4329520, rs454782, rs12136370, rs12759642, rs11184494, rs2454175 and rs156988.