premature baby 298.88.
(photo credit: Courtesy)
Some Israeli couples who carry Gaucher disease but whose fetuses would either not have symptoms or would have mild, treatable forms are aborting them because non-definitive genetic testing is available. This was reported by a team of medical geneticists at Jerusalem's Shaare Zedek Medical Center and Hebrew University-Hadassah Medical School and will be published Wednesday in the Journal of the American Medical Association (JAMA). The same situation could occur for other treatable or not serious conditions such as genetic deafness, albinism or familial Mediterranean fever.
Although genetic screening for Gaucher, which is only rarely a serious disease with severe neurological symptoms, is available at all Israeli genetic centers and subsidized by supplementary health insurance, the Israel Medical Genetics Association decided that Gaucher screening for couples is "not recommended." But it is still widely available.
Genetic counselor Shachar Zuckerman, Prof. Ephrat Levy-Lahad, Dr. Michal Sagi and others raised questions in their article about the appropriateness of certain types of genetic screenings. After contacting 10 genetic centers around the country, they identified 83 Ashkenazi couples over a period of eight years who were carriers and whose offspring would be at risk for Gaucher, 70 of them for asymptomatic or lightly symptomatic "type 1" Gaucher, 12 for moderate but treatable Gaucher and one for serious Gaucher.
Prenatal diagnosis was performed via amniocentesis or chorionic villae sampling in 76 percent of the pregnancies, and 25% of the fetuses with Gaucher were aborted. The researchers found that 15% of the asymptomatic- or mild-disease fetuses were aborted. But of 13 couples with affected fetuses who consulted with Shaare Zedek's Gaucher disease expert Prof. Ari Zimran for "directive" counseling (in which he gave recommendations of what to do), only one went for an abortion.
Their study was the first to follow up Gaucher disease carrier screening.
"We didn't know what we would find," Levy-Lahad told The Jerusalem Post on the eve of publication. "One of the big issues is that Israel's Supreme Court has ruled that physicians must tell patients about anything available in the world on their health issues. Thus if a baby were born with moderate Gaucher and a test was available and we didn't tell the couple, we could be liable for a lawsuit. But there are thousands of genetic tests, and physicians face the problem of whether they have to inform patients about all of them."
Carrier testing for fatal diseases such as Tay-Sachs were initiated here in the 1970s, and now few babies are born with it. Testing for Gaucher - which is carried by 6% of Ashkenazi Jews and is very rare in everyone else - has been available in Israel since 1995. The mutation causes the lack of an enzyme called glucocerebrosidase, which causes accumulation of a substance in the organs and can lead to anemia, fatigue, bleeding, bone diseases, swollen liver and spleen, and infections. Only in the very rare, severe type does it affect the nervous system.
The development of the synthetic enzyme for replacement therapy meant that most patients with symptoms can live normal lives, although treatment costs $75,000 to $100,000 a year.
But the screening test does not fully predict how mild or severe the disease will be, and it can cause couples whose older, healthy children were born before screening to be anxious about their future.
"We believe that geneticists started doing Gaucher screening without thinking what would be the result," Levy-Lahad said. "As a result, fetuses that would have no symptoms or only mild ones are unnecessarily being aborted."
In countries without national health insurance, such as the US, it is another story. But in Israel, diagnostics and treatment are in the basket of health services, Levy-Lahad said, adding: "People want a perfect baby, and as a professional, where do you draw the line of what the patient has to know? Maybe the effect is worse than the condition we are treating."
In an accompanying editorial for the JAMA article, Dr. Ernest Beutler of the Scripps Research Institute in La Jolla, California, wrote that the issue of carrier screening needs to be examined carefully.
"Attempting to analyze the costs and benefits of a screening program for Gaucher disease is much more complex than doing so for severe, high-penetrance disorders," he wrote. "What is the price for the anguish of parents of a fetus diagnosed to be homozygous for the [asymptomatic or mild] type? To what extent will the psychological development of a child carrying the stigma of this genotype be impaired? Will his parents protect him unnecessarily and not allow him to participate in contact sports when all his friends are on the team? How many millions of dollars will be spent on unnecessary enzyme replacement therapy for children who are fated never to develop clinical disease?"
Beutler concluded that until doctors and researchers better understand the factors that determine whether carriers of the Gaucher mutation will develop severe disease or none at all, screening for Gaucher disease "will likely do more harm than good."
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