Benefits and limitations of whole genome versus targeted approaches for noninvasive prenatal testing for fetal aneuploidies

The goal to noninvasively detect fetal aneuploidies using circulating cell-free fetal DNA in the maternal plasma seems to be achieved by the use of massively parallel sequencing (MPS). To date, different MPS approaches exist, all aiming to deliver reliable results in a cost effective manner. The most widely used approach is the whole genome MPS method, in which sequencing is performed on maternal plasma to determine the presence of a fetal trisomy. To reduce costs targeted approaches, only analyzing loci from the chromosome(s) of interest has been developed. This review summarizes the different MPS approaches, their benefits and limitations and discusses the implications for future noninvasive prenatal testing. © 2013 John Wiley & Sons, Ltd.     

Overview and recent developments in cell-based noninvasive prenatal testing

Investigators have long been interested in the natural phenomenon of fetal and placental cell trafficking into the maternal circulation. The scarcity of these circulating cells makes their detection and isolation technically challenging. However, as a DNA source of fetal origin not mixed with maternal DNA, they have the potential of considerable benefit over circulating cell-free DNA-based noninvasive prenatal genetic testing (NIPT). Endocervical trophoblasts, which are less rare but more challenging to recover are also being investigated as an approach for cell-based NIPT. We review published studies from around the world describing both forms of cell-based NIPT and highlight the different approaches’ advantages and drawbacks. We also offer guidance for developing a sound cell-based NIPT protocol.     

Integration of noninvasive prenatal prediction of fetal blood group into clinical prenatal care

Incompatibility of red blood cell blood group antigens between a pregnant woman and her fetus can cause maternal immunization and, consequently, hemolytic disease of the fetus and newborn. Noninvasive prenatal testing of cell-free fetal DNA can be used to assess the risk of hemolytic disease of the fetus and newborn to fetuses of immunized women. Prediction of the fetal RhD type has been very successful and is now integrated into clinical practice to assist in the management of the pregnancies of RhD immunized women. In addition, noninvasive prediction of the fetal RhD type can be applied to guide targeted prenatal prophylaxis, thus avoiding unnecessary exposure to anti-D in pregnant women. The analytical aspect of noninvasive fetal RHD typing is very robust and accurate, and its routine utilization has demonstrated high sensitivities for fetal RHD detection. A high compliance with administering anti-D is essential for obtaining a clinical effect. Noninvasive fetal typing of RHC/c, RHE/e, and KEL may become more widely used in the future. © 2014 John Wiley & Sons, Ltd.     

Commercial landscape of noninvasive prenatal testing in the United States

Cell-free fetal DNA-based noninvasive prenatal testing (NIPT) could significantly change the paradigm of prenatal testing and screening. Intellectual property (IP) and commercialization promise to be important components of the emerging debate about clinical implementation of these technologies. We have assembled information about types of testing, prices, turnaround times, and reimbursement of recently launched commercial tests in the United States from the trade press, news articles, and scientific, legal, and business publications. We also describe the patenting and licensing landscape of technologies underlying these tests and ongoing patent litigation in the United States. Finally, we discuss how IP issues may affect clinical translation of NIPT and their potential implications for stakeholders. Fetal medicine professionals (clinicians and researchers), genetic counselors, insurers, regulators, test developers, and patients may be able to use this information to make informed decisions about clinical implementation of current and emerging noninvasive prenatal tests. © 2013 John Wiley & Sons, Ltd.     

Ethical issues associated with prenatal screening using non-invasive prenatal testing for sex chromosome aneuploidy

Prenatal screening for sex chromosome aneuploidies (SCAs) is increasingly available through expanded non-invasive prenatal testing (NIPT). NIPT for SCAs raises complex ethical issues for clinical providers, prospective parents and future children. This paper discusses the ethical issues that arise around NIPT for SCAs and current guidelines and protocols for management. The first section outlines current practice and the limitations of NIPT for SCAs. It then outlines key guidelines before discussing the ethical issues raised by this use of NIPT. We conclude that while screening for SCAs should be made available for people seeking to use NIPT, its implementation requires careful consideration of what, when and how information is provided to users.