Circulating MicroRNAs in the Screening of Prenatal Down Syndrome.

Objective: Screening tests are recommended to identify genetic defects, chromosomal aneuploidies, and structural birth defects. Sonographic and maternal serum-based options are available for the risk assessment of aneuploidy in the first and/or second trimester. Also, invasive diagnostic methods, such as amniocentesis, are used for prenatal diagnosis, but these methods carry a tangible risk to the fetus. However, in recent years, circulating fetal nucleic acids have a promising moleculer tool in the noninvasive prenatal diagnosis of fetal chromosomal aneuploidies. In this study, we aimed to explore the usability of microRNAs (miRNAs) in this process of prenatal diagnosis.

Methods: Fourteen pregnant patients who were found to be carrying fetuses with congenital anomalies were designated as the patient group; 16 pregnant women identified as being at risk of carrying children with such anomalies-but whose fetuses were later found to be anomaly-free-were assigned to control group 1; and 13 pregnant women who had been screened and who had not been identified as being at risk made up control group 2. An analysis of miRNA expression, isolated from maternal plasma and amniotic fluid samples, was performed by quantitative real-time polymerase chain reaction.

Results: It was found that hsa-miR-629-5p, hsa-miR-320c, hsa-miR-21-5p, hsa-let-7c-5p, hsa-miR-98-5p, hsa-miR-486-5p, hsa-miR-4732-5p, and hsa-miR-181a-5p levels increased in the patient group's maternal plasma compared to that of the control group.

Conclusion: In light of these data, we believe that miRNAs may have an important role in the noninvasive prenatal diagnosis of fetal birth defects, especially Down syndrome.