Although this story was written about CF, the controversy could just as easily have been written about SCID
The number of babies born with cystic fibrosis declined by half in Massachusetts after genetic screening started to identify carriers of the gene, suggesting similar declines may be happening across the nation, according to a recent report in the New England Journal of Medicine.
The Massachusetts study is among the first to examine the implications of widespread genetic screening, which is expected to increase as scientists discover genes for other genetic disorders.
Researchers say they cannot definitively explain the decline, but they surmise that couples who learn both carry the CF gene may decide not to have children, may turn to donor sperm or eggs or may test embryos before they are implanted in the womb. Also, pregnant women who learn they are CF carriers may test the fetus and have abortions if the test is positive.
“We think genetic screening has impacted the number of babies born with this disease,” said Richard Parad, an author of the brief journal report and a physician at Children’s Hospital Boston.
The study by the New England Newborn Screening Program, at the University of Massachusetts Medical School, looked at the number of babies born with CF — a serious genetic disorder that affects the lungs and digestive system — before and after 2002. That’s when the National Institutes of Health and the American College of Obstetrics and Gynecology recommended nationwide prenatal screening to identify carriers of CF.
The simple blood test, which costs around $100 to $200, determines if a person is a carrier of the CF gene. One out of every 29 Caucasians and one out of every 65 African Americans are carriers. If both parents are carriers, each child has a one in four chance of having CF. About 1 in 3,000 babies are born each year with the disease.
The Massachusetts researchers compared the four-year periods before and after 2002 and found the number of infants with CF dropped by 50 percent after the new screening recommendation. For each year after genetic screening became more widespread, the number of CF babies dropped from about 25-30 to 15 annually. In addition, among babies born with CF, far fewer than expected had the gene mutation associated with the most severe form of the disease.
Parad said scientists should examine the repercussions of recommending that four million women each year be tested for the CF gene.
“I think you might want to see what happens when you do that kind of widespread testing,” he said. “What do people do with this information?”
Genetic screening for CF presents unique ethical questions, particularly since many people with the disease live into adulthood. “There is a tendency to act as if genetic testing is about choice and information, and not really make the connection to the consequences,” said Arthur Kaplan, director of the Center for Bioethics at the University of Pennsylvania. “I believe the reason we pay for genetic testing is partly we know people will make reproductive decisions that will lead to less prevalence of the disease.”
Kaplan said the ethical questions will become more complex as genetic screening expands.
“What if there was a test for homosexuality? Or short stature?” he asked.
In cystic fibrosis, pancreatic, intestinal and lung secretions tend to be thick, clogging organs, especially the lungs. Complications can include lung collapse, heart failure and liver damage. In the past 25 years, medical advances have doubled the average life expectancy for people with CF, according to the Cystic Fibrosis Foundation, a national organization. Life expectancy is now 37.
The organization, in a statement, called genetic testing a personal matter and said it is too early to know if the Massachusetts decline is being duplicated in other parts of the country.
Preston W. Campbell III, the foundation’s executive vice president for medical affairs, said prospective parents should know that promising drugs are in the pipeline.
“Most babies born today with cystic fibrosis will live long and full lives,” he said.
Parents involved with the New Jersey State Organization of Cystic Fibrosis said they understand the joys and frustration of raising CF children.
Bob Frees of Linden has five children, two with CF, including a 26-year-old daughter who recently underwent a double lung transplant. Frees said he and his wife are happy genetic testing was not available when his children were born.
“We would not want to have to go through those difficult decisions,” he said.
In contrast, Frees said his married son with CF fears passing the disease on to his children and wants testing.
“He doesn’t want to see a child suffer they way he has suffered,” Frees said.
Another parent, Beth Maisto of Little Egg Harbor, has three children — two with CF. She did not learn she and her husband were carriers of the gene until she was tested during her third pregnancy. The knowledge led doctors to test her older son, who had frequent respiratory problems; they found he had CF. “They sent us to counseling and asked if I wanted to terminate the pregnancy,” she said. “But I couldn’t do it.”
Life with Michael, 7, and Julie, 4, can be difficult. Each is on multiple medications. She and her husband work opposite shifts to care for their children.
“The unknown is scary,” Maisto said. “But when you have an actual child in your arms, you see it’s not that bad. My kids are the best thing in my life.”
Carol Ann Campbell may be reached at firstname.lastname@example.org.
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