Recent developments in prenatal genetic testing

Here in the USA, where most of our PIRC collaborators reside, we’ve been pretty preoccupied lately with elections and such. But while we were doing other things, prenatal genomics has continued to produce new research and developments. Here are a couple of them.

One development that has big implications for women in the UK is the approval of cfDNA screening by the UK National Health Service. This approval is not unexpected, as the UK National Screening Committee in January recommended expanding the screening program to include prenatal cfDNA screening (also known as non-invasive prenatal testing, or NIPT). However, the change will not be instantaneous; rather, it will be implemented slowly over a 3-year period, during which staff will also be trained, so that women should not expect to see this test routinely offered until 2018 or 2019. The roll-out will also be monitored by the National Screening Committee, which may recommend changes to the implementation process along the way. Said Dr. Anne Mackie of the Committee:

Key to ensuring we get this right is the work we are doing with patient groups, scientists and clinicians, to help us develop balanced informative resources for the public and health professionals. (source)

Research by PIRC collaborators has suggested that appropriate education for both patients and provider education is among the most crucial needs as prenatal cfDNA screening is implemented worldwide.


A second development that has major technological implications for prenatal genetic testing is that researchers at Wayne State University have successfully isolated fetal DNA from placental cells as early as 5 weeks gestation (3 weeks after conception). The small study showed that their technique, which uses intact trophoblast cells harvested from the mother with a Pap smear, yielded fetal fractions of 85 to 99.9%–in comparison to cell-free DNA from maternal serum, which typically yields fetal fractions of around 10%. These cells can then be sequenced for very early profiling of the fetal genome. Since the cells are from the placenta (like cell-free DNA), however, this new technique will encounter some of the same issues as current non-invasive prenatal screening, in which the placental DNA sometimes differs from that of the fetus.

Equally interesting, however, is that the team has also discovered significant differences in the expression of certain proteins in these trophoblast cells, which correlated with whether the pregnancy had a normal progression or had growth restriction or preeclampsia. The team also plans to continue this line of study, in hopes that they will find even more proteins that are markers for preeclampsia and preterm birth. This finding could be a game-changer for clinicians struggling with identifying pregnant women at risk for preterm birth, and could enable earlier interventions to help women have healthier pregnancies.


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