New strategies for noninvasive screening and prenatal diagnosis: The cell-free fetal DNA in maternal blood

Prenatal diagnosis is aimed to provide reliable clinical information to parents and physician on the risk of having babies affected by inherited anomalies or genetic disorders. Placenta is not a barrier between the pregnant woman and her genetically different fetus, but it is the centre of a complex bidirectional transfer. The discovery of circulating fetal DNA in maternal blood has disclosed new strategies to perform noninvasive testing for prenatal diagnosis, without any harm for the fetus. The possibility to measure rapidly and reproducibry fetal cell-free DNA with noninvasive techniques has warranted many clinical applications: gender detection, diagnosis of fetal aneuploidy such as 13, 18 and 21 trisomies, complications of pregnancy, X-linked diseases, cystic fibrosis, and several others.