Detection of fetal RhD gene from maternal blood

Abstract

Objective: Hemolytic disease of the newborn (HDN) is a clinic phenomenon which occurs during pregnancy due to the Rhesus (Rh) D alloimmunization between a Rh (-) pregnant woman, who has become sensitive to RhD antigens, and her Rh (+) fetus. As a result of the attack of maternal RhD antibodies on fetal RhD antigens, fetal anemia, HDN and fetal death may occur. % 40 of Rh (-) pregnant women carry Rh (-) fetus. However, all Rh (-) pregnant women are offered anti-D Immunoglobulin (Anti-D Ig) at 28 weeks' gestation in case of fetomaternal haemorrhage, so the pregnant women carrying Rh (-) fetus are exposed to blood products unnecessarily. Although the RhD of fetus can be detected, methods used for prenatal diagnosis recently are invasive tests and they can result in abortion in a certain percentage . The discovery of circulating cell-free fetal nucleic acids in maternal plasma has opened up new possibilities for non invasive prenatal diagnosis. The aim of this study was to detect prenatal RhD by analysing the presence of the RhD gene of fetal DNA in maternal blood. Material and Methods:Total free DNA was isolated from the blood of 19 Rh (-) pregnant women, who had RhD alloimmunization with their husbands, in the 11-14 th week of their pregnancy. The existence of a gene in isolated DNA was investigated with TaqMan prob and "Realtime PCR" method by using primers belonging to exon 7 of RhD gene.Results: Using a quantitative real-time PCR assay, the presence of RhD gene sequences was evaluated in the serum of patients at the onset of pregnancy. We have analyzed 19 Rh (-) pregnant women. Twelve of them were Rh (-) and the rest of them were 7 Rh (+). After birth the baby's blood groups were concordant with our results. Conclusion: Abstract ÖzetOriginal Investigation 82

Is the management of Rh-Rh incompatibility with noninvasive fetal Rh genotypingfor targeted prophylaxis cost-effective in the Turkish population?

“…Cell-free fetal DNA constitutes 3%-6% of the cell-free DNA in maternal serum (5,21). Fetal DNA can be obtained from maternal serum by the fifth week of pregnancy with this method.…”

“…Cell-free fetal DNA constitutes 3%-6% of the cellfree DNA in maternal serum (5). Cell-free fetal DNA from maternal blood is tested for the presence or absence of the RhD gene, and results are used to direct management of the pregnancy.…”

Real-Time Quantitative PCR for Detection Cell Free Fetal DNA

“…RHD was used as a test-bed to prove the effectiveness of detecting a paternally inherited allele carried bty circulating free fetal DNA in maternal plasma (Lo et al, 1997). Maternal plasma-based RHD genotyping has been succesfully implemented in our laboratories for use as a non-invasive prenatal diagnosis where alloimmunization has occured (Gunel et al, 2010). Real-time PCR has been the choice diagnostic test used.…”

Maternal plazmadaki hücre dışı serbest fetal DNA kullanılarak girişimsel olmayan fetal RhD genotiplemesinin tanısal doğruluğu

“…As a result of this application, D negative fetuses are exposed to unnecessary vaccine product [5]. According to the researchers found to D negative pregnant women who took prophylaxis have 40% off D negative fetuses [6].…”