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Thu June 7, 2012
UW's new fetal genetics test: Less risk, more controversy
Originally published on Fri June 8, 2012 9:37 am
The full genetic code of a fetus has been cracked. The technique, used by scientists at the University of Washington, could offer parents safer and more comprehensive prenatal testing in the future. It also leaps into a debate over what information parents will eventually have — and use — to decide whether to have an abortion.
The ethical questions that arise from this kind of testing abound: Discovering certain genetic diseases could lead some parents to terminate the pregnancy. Plus, NPR's Rob Stein says, the full-genome tests could lead parents to seek out positive traits, too: eye color, height, athleticism, intelligence.
"That's the theoretical possibility — that someday down the road, this can open up a real Pandora 's box of all kinds of moral and ethical problems," he tells All Things Considered host Audie Cornish.
Key to conducting the study, published in the journal Science Translational Medicine, is the fact the fetus' DNA runs through its mother's blood. Stein says this recent realization has allowed scientists to figure out new ways of extracting and analyzing that DNA. For this test, they also took a sample from the father's saliva, to determine which DNA belonged to the fetus.
Getting a sample from the mother's blood is less risky than the current prenatal tests available: amniocentesis and chorionic villus sampling.
"Those tests are what they call 'invasive,' which means they can be risky. They can cause miscarriages in women," Stein says.
He points out that in the last year or two, there have been other tests that use DNA in the blood, rather than in the uterus.
"But those tests are much more specific. ... They don't spell out every single letter in the genetic code," he says. "They look for very specific variations — usually things like Down syndrome and conditions related to that."
While a possible future filled with "designer" babies looms, Stein says that reality is still far away.
"The whole-genome sequencing for prenatal testing is something that's way, way, way off in the future," he says. "There's no way that's going to happen any time soon."
Experts tell The New York Times the process isn't "practical, affordable or accurate enough for use now."
The University of Washington researchers point out that though they can collect more data than ever, it doesn't mean they always know what to do with it.
"A full fetal genome sequence would turn up numerous mutations for which information is lacking as to whether they cause disease, posing a dilemma for expectant parents and their doctors," the Times says.
According to the report:
"[As] in other areas of clinical genetics, our capacity to generate data is outstripping our ability to interpret it in ways that are useful to physicians
Meanwhile, debates related to fetal testing are playing out in the courts. As NPR's Kathy Lohr reported in May, several states are looking at so-called "wrongful birth" laws. This kind of legislation would prevent parents from suing a doctor who doesn't warn them about fetal problems.