QRT-PCR evaluation of selected microRNAs’ expressions in the amniotic fluid and chorionic villus samples from Down syndrome pregnancies

Abstract

INTRODUCTION Trisomy 21, responsible for 95% of Down syndrome cases, is the most common viable aneuploidy. Prenatal diagnosis is based on genetic tests conducted on samples obtained by invasive procedures (1, 2, 3). OBJECTIVES AND BACKGROUND Here we show preliminary data on the expression of hsa-miR-371-3 placenta specific cluster and of 5 microRNAs mapped on chromosome 21 (hsa-miR-99a, hsa-let-7c, hsa-miR-125b-2, hsa-miR-155, hsa-miR-802). MATERIALS AND METHODS Biological material obtained by amniocentesis and chorionic villous sampling, was preserved in RNA later at -80*C until further usage. microRNA quantification was performed using dedicated TaqMan assays on synthesized cDNAs using a two-step Cells-to-Ct kit. The changes that occurred in microRNA expression were calculated using the ΔΔCt method. RESULTS We found statistically significant changes in the expression of three microRNAs (one belonging the miR371-3 cluster, the other two mapped on chromosome 21) in aneuploid samples compared to euploid samples. We found significant differences between microRNAs’ expression in samples obtained from male fetus vs. female fetus pregnancies. Data regarding the transcriptional profiles, primary microRNAs respectively, are provided by these microRNAs, through an advanced putative mechanism that explains the results. CONCLUSIONS The significance of our data is also discussed in terms of utility for antenatal diagnosis. REFERENCES 1. Chiang T, Schultz RM, Lampson MA. Meiotic origins of maternal age-related aneuploidy. Biol Reprod. 2012;86:1-7. 2. O'Connor C. Trisomy 21 causes Down syndrome. Nature Education 2008;1:42. 3. Cartier L, Murphy-Kaulbeck L. Counselling Considerations for Prenatal Genetic Screening. J Obstet Gynaecol Can. 2012;34:489–493

Keywords

• microRNA
• trisomy 21.