Today’s genetic technologies are not yet a crystal ball for seeing a child’s future, but doctors are closer than ever to routinely glimpsing the full genetic blueprints of a fetus just months after sperm meets egg. That genomic reconstruction would reveal future disease risk and genetic traits even as early as the first trimester of pregnancy. Fetal screening could theoretically detect every hint of disease-associated mutations or disease-carrier status in a fetus’s genome—sometimes outpacing geneticists’ knowledge of how to interpret such information. It could also reveal nonmedical markers for eye color or athletic prowess.
Advances in fetal cell research, coupled with the ever-dropping price of whole genome sequencing, presage the possibility of making such scans commonplace. Two years ago researchers devised two tests that could reveal a fetus’s complete genetic profile. Separate research groups sequenced complete fetal genomes after gathering traces of fetal DNA in a blood sample from a pregnant woman or by taking that blood in combination with a drop of saliva from the father. Those largely noninvasive screenings could be carried out early in pregnancy, without the small risks of miscarriage inherent in withdrawing placental tissue or amniotic fluid to hunt for a chromosomal condition such as Down syndrome. “The technology is all there to do this,” says Lisa Soleymani Lehmann, the director of the Center for Bioethics at Brigham and Women’s Hospital. “Part of the issue is cost and part of the issue is the ethical controversy, which is limiting the uptake of this—not knowing how to deal with the uncertainty of this information or how to interpret this massive amount of data.”
Indeed, whole genome sequencing could provide parents with an avalanche of unexpected and perhaps confusing data. Instead of targeted tests for a few dozen genes, future sequencing techniques could provide parents with three billion base pairs of data. The key issues inherent in any genome sequence work would plague fetal sequencing as well—namely, there is no guarantee that genetic mutations will actually result in a specific disease. And grappling with information suggesting that certain conditions may emerge in adulthood, or studying mutations with unclear significance, could be fraught with risks and challenges—impacting parents’ decision threshold for deciding to terminate a pregnancy or influencing how they rear their child.
Despite the ambiguities, parents should still be able to obtain fetal genome information after receiving genetic counseling, Lehmann and her co-authors argue in an article in the January 16 edition of The New England Journal of Medicine. That information could better inform expectant parents and enhance their ability to plan for the child’s future. Parents may emphasize diet and exercise more for a child at heightened risk of diabetes, for instance.
Whereas current prenatal tests are diagnostic—telling parents about the definitive presence of disease—prenatal whole genome sequencing would reveal susceptibility genes for issues including heart conditions, diabetes or obesity. Such a shift would drastically alter prenatal care and decision-making. Put another way, where doctors have been reluctant in the past to provide parents with genetic information for an untreatable illness, the complete genomic profile, revealed long before the fetus is born, would present genetic variants that could serve a purpose more predictive than diagnostic.
Lehmann and her colleagues are not the only ones watching the advances in prenatal screening with an arguably wary but hopeful eye. “I believe that most of us think this is still a little ways out before we are seeing significant adoption of this as an option in prenatal testing,” says Sandra Darilek, a certified genetic counselor and spokesperson for the National Society of Genetic Counselors. A group of bioethicists affiliated with the National Institutes of Health also penned an analysis in 2012 forecasting a future that included such scans. They called both for further recommendations about what data parents should ask for and advised that children should have the right to be told about adult-onset diseases as adults, rather than during childhood. Two years later no formal recommendations have been released by genetic societies outlining what diseases should be revealed to prospective parents, and there are still no clear answers about where a child’s rights to be protected from such data end and a parent’s prerogative to obtain, and perhaps act on it, begin.
Whereas adults can choose to undergo genome sequencing, an unborn child cannot consent to screening its genes. Still, such concerns should not keep parents from obtaining data they want to see about their fetus, Lehmann says. “Parents have a right to this information, and there may be significant benefits to the child of a parent having this information.” And more genetic counselors and electronic educational resources will be needed to help guide expectant parents through such sequencing decisions, she says.
Enthusiasm for arming parents with such broad genetic profiles has stoked concern in some circles that screenings would prompt a quest for so-called perfect babies, free of any genetic abnormalities or possessing desirable traits of beauty, intelligence or athleticism. But many parents would forgo whole genome sequencing, Lehmann and her colleagues argue, adding that such concerns should not justify withholding information about genetic markers for future illness. “This isn’t something physicians should be deciding,” Lehmann says. “If parents want to have this kind of information, their voices need to be heard.”