Noninvasive Prenatal Testing for Fetal Aneuploidy

ABSTRACT After decades of research with a wide range of putative methodologies, at last a commercially viable technique has emerged for the noninvasive prenatal testing (NIPT) for the most common fetal aneuploidies, the massively parallel shotgun sequencing (MPSS). Recently, a number of groups have validated this technology to accurately detect most common trisomies as early as the 10th week of pregnancy with results available 1 to 2 weeks after maternal sampling. Several molecular techniques have been proposed for the detection of trisomies 21, 18 and 13, mainly by two different approaches in analyzing the cell-free fetal (cff) DNA: quantitative and singlenucleotide polymorphism (SNP)-based methods. Among them and to address some of the limitations of counting techniques, a new method called NATUS algorithm (Next-generation Aneuploidy Testing Using SNPs) has been recently introduced. This approach, as a targeted and noncounting technique, offers numerous advantages, although more evidence is needed from large prospective studies. Published studies have demonstrated that diagnostic parameters of NIPT are better than those of the current first trimester prenatal screening risk assessment for fetal trisomy 21. NIPT of trisomy 21 by MPS with or without preselection of chromosomes is promising and likely to replace the prenatal serum screening test that is currently combined with nuchal translucency measurement in the first trimester of pregnancy. However, before NIPT can be introduced as a screening test, more evidence is needed from large prospective diagnostic accuracy studies in first trimester pregnancies. How to cite this article Gabriel CC, Echevarria M, Rodríguez M, Serra B. Noninvasive Prenatal Testing for Fetal Aneuploidy. Donald School J Ultrasound Obstet Gynecol 2013;7(4):443-452.