THE CELL-FREE DNA DETECTION AND ANALYSIS AS THE NEW NON-INVASIVE PRENATAL DIAGNOSTICS OPTION

Abstract

Screening procedures for chromosomal abnormalities in fetuses are a standard of care for pregnant women. Ultrasound and maternal serum analysis are traditional prenatal screening methods with detection rates between 75%-95%, and considerable false-negative and false-positive results. Also, both require follow up by invasive diagnostic tests in screen-positive cases, mostly amniocentesis and chorionic villi sampling, which are associated with notable risk of pregnancy loss. One of the innovative non-invasive prenatal testing (NIPT) options is the analysis of cell-free DNA (cfDNA) in plasma, which is detected in maternal circulation in a relatively high concentration. Commercial tests for cfDNA in maternal blood have recently become available. Cell-free DNA detection tests do not separate fetal from maternal DNA but use full cfDNA complement and analyze difference in total amount of sequenced DNA fragments, with the help of sophisticated data analysis software. It seems that cfDNA technology testing is highly accurate and has a very high sensitivity, so the difference compared to routine serum sample screening shows its significant superiority. However, cfDNA positive results still need confirmation by the invasive testing. The cell-free DNA analysis aims to become the first choice NIPT option due to its safety and high accuracy rate. The final goal is to develop the reliable method that could eventually replace invasive prenatal testing procedures.