Chris Kaposy considers the future trajectory of non-invasive prenatal testing and the implications of using this testing method to conduct prenatal whole genome sequencing.
Non-invasive prenatal testing is a technology that allows fairly accurate detection of genetic differences in a fetus with only a blood sample from a pregnant woman. This testing has an advantage over maternal serum screening (and other screening tests) because it is more accurate. The benefit of better accuracy is that fewer women are referred to invasive testing (such as amniocentesis) which carries a risk of miscarriage. Current non-invasive tests screen for Down syndrome, other trisomies like trisomy 13 and 18, sex chromosome differences, and some tests screen for small deletions of genetic material at the subchromosomal level, as well as small additions.
Non-invasive prenatal testing is a big business. The testing labs marketing these tests are constantly in competition, and frequently sue each other over patents. Some provinces will pay for non-invasive prenatal testing with public funding in certain circumstances. But at present most of the time pregnant women must pay out of pocket. One online advertisement for this testing in Canada states that the test costs $550-$795. Most women who are given prenatal diagnosis that their fetus has Down syndrome or another genetic condition terminate their pregnancies.
The familiar, disability-positive, objection to non-invasive prenatal testing is based on the fact that these tests are directed at detecting disabilities, and that termination is the most common outcome after prenatal diagnosis of a genetic difference. Some view non-invasive prenatal testing as a massive corporate and professional effort to improve technologies that are used to avoid the birth of people with cognitive disabilities. The most prevalent genetic difference for which there is prenatal testing is Down syndrome. Most people with Down syndrome tend to enjoy their lives. According to the disability critique, a lot of money and effort is being spent to eliminate people who, for the most part, enjoy their lives. To many people with these conditions and their advocates, the use of this technology is offensive, threatening, and discriminatory.
Less familiar, however, might be the future trajectory of this technology. Non-invasive prenatal tests appear to be expanding almost daily to more and more indications. The prenatal testing industry appears to be moving towards the development of technologies that will enable us to sequence the entire genome of a fetus, and have information about every single base-pair of the fetal genome without exposing the pregnant woman to any risk of miscarriage. Like today’s non-invasive tests, tomorrow’s prenatal whole genome sequencing technologies might require a simple maternal blood sample out of which can be derived fetal genetic material.
If such technologies are developed, it is not because there is any clinical need to have complete information about every fetal genome. Rather, we are heading in the direction of non-invasive prenatal whole genome sequencing for two reasons unrelated to clinical need. The first reason is technological momentum. The increasing scientific and technological sophistication of the prenatal testing enterprise is moving us closer to developing clinical products that give prospective parents all of this genetic information about their fetuses. The second reason is the competition for profit between testing companies, who incidentally are increasingly being subsumed by large pharmaceutical corporations. Whole-genome tests could be profitable, so the corporate entities involved will develop these tests.
As some bioethicists have realized, if prenatal whole-genome sequencing becomes available, pregnant women and their partners will be subsumed by a flood of genetic information about their fetuses. There will be so much information, anyone would have trouble making sense of it all. Anyone undergoing this testing would require intensive genetic counselling. Some bioethicists are beginning to propose ways of managing this extensive scope of fetal genetic information, and empowering prospective parents to make decisions on the basis of it.
Some genetic information is only probabilistic. For instance, some genes are associated with a probability that the child with have autism, for instance. If you are given a probability that your potential child will develop autism, how should this information be handled? People with autism tend to enjoy their lives as well. For any decision to terminate such a pregnancy, there will be a probability that the prospective child would not have developed autism. Future pregnancies could yield the same result. Such decision-making could only be highly fraught and stressful for prospective parents.
Whole-genome information could also give parents unprecedented genetic control over their future children. Such control could change cultural practices relating to pregnancy. Relationships between parents and children could change in unforeseen and perhaps undesirable ways. If this is the direction in which non-invasive prenatal testing is heading, we should be aware of, and prepared for, these frightening possibilities.
For more, on this topic see Choosing Down Syndrome: Ethics and New Prenatal Testing Technologies, by Chris Kaposy, which will be available in March 2018 (MIT Press).