Higher level of embryo testing raises questions about possibility of creating "designer babies".
The procedure combines the newest techniques in genetic testing and in vitro fertilization. As the Human Genome Project reveals the genes responsible for the development of cancer, Alzheimer's, and other diseases, advanced embryonic testing opens the door to the creation of babies who are free of genetic predispositions to late-onset disorders. But such testing also raises a host of ethical questions, suggesting to some that it is another step toward creating "designer babies" with preselected genetic qualities.
The announcement was made by researchers at Genetics Institute, best known for pioneering the technique called preimplantation genetic diagnosis (PGD), which tests human embryos created in the lab before they are implanted in the womb. Institute scientists stirred worldwide debate last year following the birth of Adam Nash, who had been selected from among 15 embryos created by his parents. Adam's embryo was chosen because it was a good bone marrow match for his older sister, who suffered from a fatal anemia. Cells transplanted from Adam's umbilical cord saved his sister's life-the first reported case of genetic selection of an embryo to rescue a living person.
In the new case, Institute researchers worked with a New York couple concerned that their future children would inherit Li-Fraumeni syndrome, a predisposition to many forms of cancer caused by a mutation in the P53 tumor-suppressor gene. The 38-year-old husband was the carrier of the faulty gene and was first diagnosed with cancer at age 2 and then again at age 31. After testing 18 early-stage embryos, the scientists found 7 with normal P53 genes. Two of those embryos were transferred into the mother, resulting in a successful pregnancy and the birth of a healthy baby boy without the P53 mutation.
Institute director Yury Verlinsky, MD said that prenatal testing via amniocentesis or chorionic villus sampling (CVS, which he pioneered) could detect such genetic vulnerabilities to cancer when the fetus is in the womb. He and others would not perform such testing at that time, however, because of ethical concerns about aborting a fetus based on genetic predisposition alone.
"On the other hand, I would have no hesitation for selecting an early-stage embryo for implantation in the uterus that is free of predisposing genes," said Verlinsky. "No hesitation at all."
Also present at the announcement was the father of in vitro fertilization, retired Cambridge (England) University physiologist Robert Edwards who with his partner the late gynecologist Patrick Steptoe created the first test-tube baby Louise Joy Brown in 1978. "Preimplantation genetic diagnosis has grown slowly but steadily, and I predict it will explode in the years to come," said Edwards. "It is performed at about 29 medical centers worldwide, mostly to uncover single-gene disorders-but the ethical problems in different countries appear to be overwhelming."
One ethical concern posed by Arthur Caplan, PhD, director of the center for bioethics at the University of Pennsylvania in Philadelphia, is that scientists are culling embryos predisposed to diseases that may never happen-or which may be curable, should they develop when the person is 40 or 50 years old. And Caplan pointed out that since there are no standards for PGD testing, it is unclear what level of error rate-"and all tests have error rates"-would be acceptable.
PGD "also raises questions as to where we draw the line between eradicating disease and personal preferences, such as height, eye color, or gender," said Laurie Rosenow of the Institute for Science, Law and Technology, Chicago-Kent College of Law. "If I can find someone willing to use [PGD] to select for these traits, regardless of the reason, there is nothing to prevent it."
In addition to these ethical issues, PGD is plagued by troublesome legal concerns. "There is practically no regulation in this field; the industry," Rosen reported. "In fact, it is being regulated by the individual physicians and clinics who offer these services."
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|Comment:||Higher level of embryo testing raises questions about possibility of creating "designer babies".|
|Article Type:||Brief Article|
|Date:||Jun 30, 2001|
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