Human Embryos in Britain May Be Screened for Cancer Risk
Thursday, May 11, 2006
British regulators yesterday ruled that fertility clinics may screen out human embryos carrying genes that raise the risk of cancer in adulthood -- a move the government said could prevent future suffering but that others said was proof that the age of handpicked, "designer" babies is at hand.
The Human Fertilisation and Embryology Authority, which oversees tests involving human embryos in Britain, had previously allowed the use of genetic tests only to eliminate "test tube" embryos bearing genes for fatal childhood diseases.
The new decision expands that policy to include some genes that significantly increase the odds -- but do not guarantee -- that a person will get cancer. The policy also for the first time includes diseases -- primarily breast, ovarian and colon cancer -- that do not strike until adulthood and often respond to treatment.
Similar embryo screening tests have been used in the United States for years. But because they are not regulated or tracked, no one knows how often they are performed or the full range of conditions being screened for.
Some experts fear that as scientists discover genes affecting traits such as obesity, addiction, intelligence or height, a market in elective embryo screening may emerge -- backed by evidence that selected children would be healthier, happier and more successful.
The kind of testing in question, known as preimplantation genetic diagnosis, is conducted on one or two cells removed harmlessly from a three-day-old test tube embryo created by in vitro fertilization. If a cell is found to harbor an unwanted gene, that embryo is not used.
"The role of medicine has always been to try to relieve pain and suffering and to try to improve the quality of life for people," said HFEA chair Suzi Leather, in a statement. "The decision today deals only with serious genetic conditions that we have a single-gene test for. We would not consider mild conditions -- like asthma and eczema -- which can be well-managed. . . . We would not consider conditions like schizophrenia where a number of genes have been identified but there is no single gene that dictates the condition."
The genes noted in the decision are BRCA1 and BRCA2 -- which confer an approximately 80 percent lifetime risk of breast cancer (and, with BRCA1, a 40 percent chance of ovarian cancer) -- and HNPCC, which carries a 78 percent lifetime risk of colon cancer. BRCA cancers can strike women in their thirties and forties. Half of the people carrying HNPCC get colon cancer by age 50.
The ruling is not a blanket acceptance but means the HFEA will now consider screening requests on a case-by-case basis.
"It raises a number of obvious ethical issues," said Bert Vogelstein, a medical geneticist at Johns Hopkins University and a co-discoverer of the HNPCC gene. Most people he has spoken with, including patients and their relatives, don't think embryo screening for the disease is justified, Vogelstein said. "But there are some who have seen their families devastated by these diseases . . . and they are not so sure."
Some groups in Britain had vigorously opposed the move. And in the United States, the ruling was lambasted by the Catholic Church.
"There does seem to be grade inflation here," said Richard Doerflinger, deputy director of pro-life activities for the U.S. Conference of Catholic Bishops. "You need fewer and fewer things wrong with you to fail to measure up."
The British Medical Association said it welcomed the decision "to extend the criteria for embryo selection." Its chief of ethics and science, Vivienne Nathanson, tried to allay fears of a slippery slope.
"We do not see that today's decision is moving towards 'designer babies,' " she said in a statement. "There is a world of difference between a parent not wanting their child to develop breast cancer and someone wanting a child with blue eyes and blond hair."