The biology and diagnostic applications of fetal DNA and RNA in maternal plasma

As conventional methods for prenatal diagnosis, such as amniocentesis and chorionic villus sampling, are associated with a risk of fetal loss, the pursuit of safe noninvasive alternatives has been a long-sought goal in medicine. The discovery of the presence of extracellular fetal nucleic acids in the maternal circulation has offered new avenues for the realization of this goal. The number of potential applications of fetal nucleic acids analysis from maternal plasma has grown substantially in recent years. Noninvasive prenatal rhesus D genotyping has been introduced into routine use by some centers. Although certain limitations are preventing the wider adoption of circulating fetal nucleic acids analysis for clinical use, promising developments with the potential to overcome the present limitations have emerged recently. Albeit the rapid growth in the number of potential applications, much work is required to elucidate the little-known physiological mechanisms of circulating fetal nucleic acid release and clearance. Furthermore, in recent years, there is a greater appreciation of the impact of certain technical factors on the interpretation of research data on circulating fetal nucleic acids. Further rapid development in this emerging area is expected over the next few years. (C) 2004, Elsevier Inc.