Uncertainty of fetal fraction determination in Non-Invasive Prenatal Screening by highly polymorphic SNPs

Fetal fraction and the chromosome representation are the two key quantities used in Non- Invasive Prenatal Screening (NIPS) to determine the aneuploidy status of a fetus. Several methods for fetal fraction determination have been proposed in the literature, including a class of the methods, denoted snpFF, based on high-coverage targeted sequencing of highly polymorphic Single Nucleotide Polymorphisms (SNPs). The variant of snpFF, investigated here, has similar properties as the other variants of snpFF. We point out that the variability of the individual informative SNPs-based estimates of fetal fraction increases with the increase of fetal fraction. At 4% fetal fraction the Inter-Quartile Range (IQR) of the individual estimates of fetal fraction is around 3% and it increases to 6% at 15% fetal fraction. snpFF cannot detect fetal fraction below 2.5% because the number of informative SNPs becomes too small, even zero

DNA Polymorphisms in Pregnant Women with Sticky Platelet Syndrome

Sticky platelet syndrome (SPS) is a thrombophilia caused by the increased aggregability of platelets in response to the addition of low concentrations of epinephrine (EPI) and/or adenosine diphosphate (ADP). Some of the single nucleotide polymorphisms (SNP), alleles and haplotypes of platelet glycoprotein receptors were proved to have a role in the etiology of thrombotic episodes When comparing SPS and the control group, in VEGFA rs3025039, the p value for both CC vs. TT and CT vs. TT analyses was <0.001. Interestingly, no minor TT genotype was present in the SPS group, suggesting the thrombotic pathogenesis of recurrent spontaneous abortions (RSA) in these patients. Moreover, we found a significant difference in the presence of AT containing a risky A allele and TT genotype of ALPP rs13026692 (p = 0.034) in SPS patients when compared with the controls. Additionally, we detected a decreased frequency of the GG (CC) genotype of FOXP3 rs3761548 in patients with SPS and RSA when compared with the control group (p value for the CC (GG) vs. AA (TT) 0.021). This might indicate an evolutionary protective mechanism of the A (T) allele in the SPS group against thrombotic complications in pregnancy. These results can be used for antithrombotic management in such pregnant patients