Cell-free Fetal Nucleic Acid Identifi er Markers in Maternal Circulation

From the discovery of cell-free fetal (cff)-DNA in 1997 so far, many studies have been performed on various aspects of cff-nucleic acid. It is undoubted that currently, invasive prenatal diagnosis progresses to the noninvasive test. However, there are many problems. One of the most challenging issues in this fi eld is differentiation and detection of the small amount of cff-nucleic acid in maternal plasma. Many markers and methods have been used for this purpose. This review makes an attempt to review and compare the studies in the fi eld. Six identifi er markers including Y-specifi c sequence, polymorphisms, epigenetic difference, DNA size difference, fetal mRNA, and microRNA as well as the advantages and disadvantages of each marker are discussed. This review provides a relatively perfect set on cff-nucleic acid biomarkers in various physiological and pathological status of pregnancy, helping to review and compare the prior obtained results, and improving designation in future studies.