Non-Invasive Prenatal Testing: the tipping point towards mainstream genetic testing?

The emerging use of Non-Invasive Prenatal Testing, or NIPT, may mark an important milestone in the adoption of genomic medicine technologies – the one that gets the attention of primary care doctors and that makes genetic testing a mainstream reality. The use of genomics in medicine has had the biggest clinical impact on the fields of cancer and rare disease diagnosis but have yet to penetrate the realm of the day-to-day world of primary care. NIPT, a new technology for prenatal screening, is poised to change that.

NIPT enables screening for Down syndrome and other fetal chromosomal anomalies. NIPT detects and characterizes cell-free DNA from the fetus that circulates in the mother’s blood. It is a simple blood test and carries none of the risk of pregnancy loss that can occur with similar, but invasive, tests such as amniocentesis. It can also be done much earlier in the pregnancy, as early as nine weeks gestation. Because of this, use of the test is increasing rapidly, with the potential to be used for a much wider range of pregnancies than is currently the case for amniocentesis or other such tests. Already about 20% of the 4 million babies born in the USA each year are being tested this way.

It is not yet clear whether NIPT should replace invasive testing as the primary screen. At the moment only Ontario has moved ahead with funding the test (for mothers over 40 and other specific circumstances) but not as a stand-alone test; follow-up with an invasive test is recommended to confirm a positive result. One aim of the pan-Canadian clinical research project Pegasus is to determine whether NIPT should become the primary screen for chromosomal anomalies. This project is at the mid-point of its four year span. The Pegasus team estimates that adoption of NIPT would avoid up to 9000 amniocentesis procedures each year in Canada, and could prevent the loss of up to 70 normal fetuses.

The ease and increased safety of NIPT makes it appealing for pregnant women outside Ontario’s current eligibility criteria. Women can access the test privately at a cost of between $800-1,200.

By: Kathryn Deuchars, Director, Ontario Personalized Medicine Network

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