Noninvasive Prenatal GeneticTesting Using Maternal Serum

Triple screening revealed abnormalities caused by aneuploidy by detecting three chemicals found in maternal serum, human chorionic gonadotropin, unconjugated estriol, and alpha-fetoprotein. Quadruple screening The same chemical was tested by addition of inhibin A (Farrell). These tests, with the exception of women experiencing multiple pregnancies, "All pregnant women serum alpha fetoprotein screening examples" regardless of the risk of severe malformations of the brain and spine in infants with Down's syndrome or neural tube defects is there. (75, press Brody).

Fetal cells known to be present in maternal circulation are attractive and noninvasive prenatal diagnostic methods. Fetal cells immunoisolated due to low purity can only be used for prenatal diagnosis of β thalassemia in women with different mutations. Recently, this problem has been overcome by developing a technique that can separate a single fetal baby from maternal blood into erythrocytes by microscope microscopy, thereby analyzing the two fetal genes in a single cell You can do. However, this procedure is related to some technical and biological problems and can not be applied widely. (35) The discovery of free fetal DNA in maternal plasma laid the foundation for the development of another non-invasive prenatal diagnostic method. (35)

Fetal DNA in maternal plasma and serum has been shown to be a useful material for fetal sex determination and early pregnancy screening test for abnormal pregnancies. Maternal serum samples were obtained from 81 pregnant women between 5 and 10 weeks gestation. Fetal sex was determined by conventional polymerase chain reaction (PCR) to detect Y chromosome sequence (DYS 14) in maternal serum early in pregnancy and was confirmed by examining newborn after birth. Real time quantitative analysis of SRY and β globin genes was also performed to determine fetal sex and quantify fetal DNA concentration in maternal serum at early pregnancy. When using conventional PCR, the total sensitivity for identifying the male fetus is 95%, but after 7 weeks the sensitivity is 100%, whereas in real time quantitative PCR the total sensitivity after 5 weeks is It is 100%.

Qualitative and quantitative analysis of fetal DNA in maternal serum to determine embryonic early pregnancy