MicroRNAs as Biomarkers for Birth Defects

Abstract: It is estimated that 2-4% of live births will have a birth defect (BD). The availability of bi-omarkers for the prenatal detection of BDs will facilitate early risk assessment, prompt medical interven-tion and ameliorating disease severity. miRNA expression levels are often found to be altered in many diseases. There is, thus, a growing interest in determining whether miRNAs, particularly extracellular miRNAs, can predict, diagnose, or monitor BDs. These miRNAs, typically encapsulated in exosomes, are released by cells (including those of the fetus and placenta) into the extracellular milieu, such as blood, urine, saliva and cerebrospinal fluid, thereby enabling interaction with target cells. Exosomal miRNAs are stable, protected from degradation, and retain functionality. The observation that placental and fetal miRNAs can be detected in maternal serum, provides a strong rationale for adopting miRNAs as non-invasive prenatal biomarkers for BDs. In this mini-review, we examine the current state of research in-volving the use of miRNAs as prognostic and diagnostic biomarkers for BD.