Genome-wide miRNA profiling in plasma of pregnant women with down syndrome fetuses

Abstract

Down syndrome (DS) is one of the most common causes of intellectual disability and new approaches allowing its rapid and effective prenatal detection are being explored. In this study, we investigated the diagnostic potential of plasma microRNAs (miRNAs). This study builds upon our previous study in DS placentas, where seven miRNAs were found to be significantly up-regulated. A total of 70 first-trimester plasma samples from pregnant women were included in the present study (35 samples with DS fetuses; 35 with euploid fetuses). Genome-wide miRNA profiling was performed in the pilot study using Affymetrix GeneChip™ miRNA 4.1 Array Strips (18 samples). Selected miRNAs were then analysed in the validation study using quantitative reverse transcription PCR (RT-qPCR; 52 samples). Based on the current pilot study results (12 miRNAs), our previous research on chorionic villi samples (7 miRNAs) and the literature (4 miRNAs), a group of 23 miRNAs was selected for the validation study. Although the results of the pilot study were promising, the validation study using the more sensitive RT-qPCR technique and a larger group of samples revealed no significant differences in miRNA profiles between the compared groups. Our results suggest that testing of the first-trimester plasma miRNAs is probably not suitable for non-invasive prenatal testing (NIPT). Different results could be theoretically achieved at later gestational ages; however, such a result probably would have limited use in clinical practice.

Keywords: Down syndrome; Fetal aneuploidy; Liquid biopsy; NIPT; Trisomy 21; miRNA.

Fig. 1

Scatter plot displaying compared groups of samples after principal component analysis (PCA). Samples with fetal trisomy (blue) are clearly separated from samples with euploid fetuses (red). (Color figure online)

Fig. 2

Heatmap displaying clear separation of pregnancies with DS fetuses (T21; orange) in comparison with controls (K; red) according to expressions of 61 miRNAs with the lowest p-value (fold change value was not considered). These data are based on the results of the pilot study (miRNA arrays). Most of the dysregulated miRNAs are down-regulated in the DS group of plasma samples (44 miRNAs). (Color figure online)