Scientists are now able to sequence almost the entire genome of a fetus using a blood sample from the mother and saliva from the father. This new non-invasive approach — in contrast to amniocentesis, which involves sampling fluid from the uterus and carries a slight risk of miscarriage — means that virtually the entire DNA of an 18-week-old fetus can be determined. Prenatal testing for a number of genetic disorders could be a real possibility very soon. Expecting parents could soon find themselves faced with some wrenching ethical decisions, should the tests reveal that their fetus has a genetic disorder.
New Study: “Noninvasive Whole-Genome Sequencing of a Human Fetus”
Genome scientists at the University of Washington used new high-speed DNA sequencing techniques along with statistical and computational modeling to create the test, which can determine a fetus’ genome with up to 98 percent accuracy. They drew on research from the 1990s that found that a pregnant woman’s blood plasma contains cell-free DNA from her fetus and that these fragments can be genetically analyzed. Indeed, there are already commercially available tests that rely on analysis of fetal DNA fragments to determine a fetus’ gender, paternity and whether it might have Down Syndrome.
The new test would allow for the detection of Mendelian disorders, which result from the mutation of a single gene and include cystic fibrosis, Tay-Sachs disease and Marfan syndrome. Besides such inherited genetic disorders, the new test can potentially identify de novo or spontaneous mutations, which are responsible for the majority of genetic defects and which have been linked to disorders including schizophrenia and autism. De novo mutations are thought to account for about 10 percent of cases of mental retardation and learning disabilities.
The research, which was published in the Science Translational Medicine, could enable doctors to screen fetuses for some 3,500 genetic disorders.
Parents Could Face Wrenching Ethical Questions From Prenatal Testing Results
While analyzing one fetus’ DNA would currently cost about $20,000 to $50,000, researchers predict that, due to fast-moving developments in DNA sequencing, the test could be widely available in three to five years.
Some 85 percent of expecting parents who learn their fetus has Down Syndrome choose to abort. As the New York Times quotes Marcy Darnovsky, associate executive director of the Berkeley-based public interest group, the Center for Genetics and Society, the test could lead to scenarios in which people are able to decide “who deserves to be born” — the prospect of “designer babies,” of parents perhaps choosing to end a pregnancy because a fetus does not have certain desired traits. Could people even start requesting that potential partners undergo genetic testing at some point in the dating process?
What If There Were a Prenatal Genetic Test For Autism?
What parents decide to do with such information will be certainly highly personal. When I first heard about a prenatal test for autism possibly existing in the future, I thought back to the day in 1996 when my OB-GYN explained about testing for Down Syndrome. My immediate thought was that, “whatever” our baby might have or be, we would love him and care for him all the same.
But that might not be the right choice for all parents, for all mothers: Women and families must have the right to choose what is best and live with the results.
My son Charlie is on the moderate to severe end of the autism spectrum. He was diagnosed with autism back in July of 1999 shortly after his second birthday. I have always felt we and he were lucky to know so early, as we were then able, in very short order, to start him in intensive educational therapy and other treatments. None of these have “cured” him from autism and, after spending thousands of dollars and putting our careers on hold or pretty much changing our whole lives and moving around the country to find him the best possible school and after years of angst and arguing with school districts to provide him with the services he needs, Charlie has many, many challenges. A previous generation would have probably institutionalized him at a young age as he little language, tests as mentally retarded, can have some really severe behaviors.
It is true. If Charlie were not with us, I would not have been up till 4am Thursday morning doing laundry because, with his minimal speech, Charlie could not tell me that his bed was wet and I did not discover that till 2am. There would not be a dent in my neighbor’s car after Charlie, in the throes of an anxiety attack on Tuesday morning with the end of the school year imminent, ran out the front door and right at the car, because it was in his path as he ran across the street.
But how could there not be a boy who has ridden bikes all over New Jersey with my husband? Who got us all to cheer when he could finally say his name clearly (he was around 7 years old)? Who shows how intelligent he is and how much he understands all without using any words? Who did his best to communicate, in his non-verbal way, that he felt really bad about the neighbor’s car and that he is trying his very best? Who we simply love more every day?
Every day with Charlie is not always so easy, but every day (even the toughest ones) is good because he is with us.
“Not Science Fiction Anymore”
As Jay Shendure, associate professor of genome sciences at the University of Washington and the supervisor of the research team, said, more detailed prenatal genetic testing is “not science fiction anymore.” Soon we will be able to know quite a lot about an unborn child and at an earlier stage in his or her life. But what parent can lok into a crystal ball and know the whole course of what might happen to a child? A child might have all the athletic ability in the world but really prefer playing the violin rather than football.
Rather than fear what science has to tell us, we need to acknowledge that we can now know quite a lot more than we might like about a very young fetus and school ourselves to make the choices we will need — we need — to make.
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