FOETAL RHESUS D AND SEX GENOTYPING FROM THE PLASMAS OF RH-NEGATIVE PREGNANT WOMEN IN DUHOK

ABSTRACT Background: This prospective study was done to evaluate the benefit of Real-time Polymerase Chain Reaction in the determination of RHD and SRY of the fetuses in the plasma of Rhesus D-negative enrolled ladies. Methods: Thirty-nine pregnant Rh-negative females with (RhD+) partners were registered in this study. Blood samples were taken from those participants whose pregnancy age was from 20 -28 weeks for the purposes of fetal RHD genotyping and DNA extraction/purification. Real-time PCR was used to determine the RH and sex genotype using particular RHD, SRY, and GLO gene primers and probes. Results: Out of the total 39 samples, 28/39(71.8 %) were positive for Rhesus D antigen and 11/39 (28.2 %) were negative. The results of prenatal fetal RHD genotyping based on exons 7, and 10 combined were concordant with postnatal RhD phenotyping in 94.9% of cases (37/39) with a sensitivity & specificity of 93.3 and 100% respectively, and precision was 100%. For the gene SYR, there was a concordance rate of 92.3% between the fetal sex genotype and the newborn sex with one false-positive (2.6%) and two false negatives (5.1%) results leading to a precision of 95.2%. Conclusion: The study demonstrated great accuracy of the Real-Time PCR technique through the usage of cffDNA for the genetic study of the fetal RHD and SYR genes and implicates the effectiveness of this procedure for predicting the necessity of Anti-D immunoprophylaxis in pregnant women whose fetuses have a peril of hemolytic anemia of the newborn due to RhD incompatibility between partners.