MicroRNA biomarkers for early detection of embryonic malformations in pregnancy

Abstract

Congenital birth defects, manifested in newborn infants, are formed during early embryogenesis. Targeted and individualized interventions to prevent birth defects require early detection of risk and signs of developmental abnormalities. Current diagnosis of structural anomalies largely relies on ultrasonography, which can only detect abnormities after their formation in fetuses. Biomolecules, mainly proteins, in maternal blood have been used as indicators of fetal anomalies; however, they lack adequate sensitivity for detecting embryonic malformations. Recently, cell-free microRNAs (miRNAs) have been found in blood and evaluated as biomarkers for diseases. Expression of certain miRNAs in maternal plasma has been shown to be correlated with birth defects in infants. Although their reliability and sensitivity remain to be validated, miRNAs, which can be amplified and sequenced, are potentially sensitive and specific biomarkers for early embryonic dysmorphogenesis.

Keywords: birth defect; diagnosis; embryonic malformation; miRNA.

Fig. 1

Diagrammatic illustration of embryonic miRNA biogenesis and secretion to maternal circulation. Transcription of miRNA genes generates pri-miRNAs in the nucleus of embryonic cell. pri-miRNAs are processed into pre-miRNAs and transported to the cytoplasm. pre-miRNAs are cleaved into double-stranded small RNA, and further separated into single-stranded miRNAs. miRNAs are either involved in post-transcriptional regulation of mRNAs or secreted into extracellular space and transported into maternal circulation.