“Non-invasive prenatal testing (NIPT) is based on analysis of cell-free DNA (cfDNA) in maternal blood. The majority of cfDNA in maternal blood originates from the mother herself, with the fetal component (cffDNA) contributing approximately 10–20% of the total. cffDNA is present in maternal blood from early pregnancy. It emanates from the placenta, but represents the entire fetal genotype and is rapidly cleared from the maternal circulation with hours of delivery, making it pregnancy specific. If the fetus has Down syndrome (DS), there will be slightly more chromosome 21-specific DNA in the maternal circulation. With technological advances it has become possible to deliver highly accurate single-molecule counting and thereby detect small changes in the number of sequences on the chromosome of interest in blood. This approach forms the basis of NIPT for aneuploidy, a maternal blood test that can be performed in early pregnancy to significantly refine the DS risk, and reduce the need for invasive testing such as chorionic villus sampling (CVS) or amniocentesis.”
This abstract is from the Genomics Education Programme-affiliated manuscript published in July 2017 in the academic journal British Journal of General Practice. The full article can be obtained either via the sidebar’s Document Download, or via visiting the hosting journal’s webpage at: https://doi.org/10.3399/bjgp17x691625
