Genetics for the Community

Few legacies are more lethal than Tay-Sachs disease, a rare ailment that occurs almost exclusively among Jews of Eastern European ancestry. Caused by an inherited enzyme deficiency, the disease begins to affect infants at about six months of age, causes brain deterioration, and usually kills the patient before his fifth birthday. Science has yet to discover either a cure or a treatment. But doctors at Baltimore's John F. Kennedy Institute believe that they can prevent it. In a unique experiment to bring genetics to the community, they are seeking to identify those who carry the deadly Tay-Sachs gene so that the birth of doomed infants can be avoided.

The Baltimore program owes its origin to several recent scientific discoveries in the field of molecular biology. One was the identification of the enzyme hexosaminidase-A, the lack of which causes Tay-Sachs disease. Another was the development of a technique for taking cells from the amniotic fluid, the clear, amber liquid in which the developing fetus floats, and analyzing the cells for the presence-or absence-of the essential enzyme. The most important step, however, was perfecting a simple blood test to identify adults who carry the defective gene but are themselves unaffected by it.

Pulpit Participation. The screening campaign is being conducted by Dr. Michael Kaback, an assistant professor of pediatrics at the Johns Hopkins University School of Medicine, and Dr. Robert Zeiger of the National Cancer Institute. Says Kaback: "A successful genetic counseling program requires three things. First, the population at risk must be easily identifiable. Second, there must be a simple, inexpensive method of detecting carriers of the disease. Third, there must be a means of diagnosing the disease in utero." Many diseases meet two of the three criteria. Tay-Sachs is the only disease that meets all three.

There are more than 240,000 Jews in the Baltimore-Washington area, and the doctors decided to focus on those most likely to bear children: 80,000 people between the ages of 18 and 43. To reach and test this high-risk population, Kaback and Zeiger sought the support of local rabbis and leaders of Jewish organizations. Few refused to provide it. Rabbis took to their pulpits to inform their congregations about the disease and to urge them to participate in the experiment. Jewish women's organizations not only distributed thousands of leaflets but provided volunteers to conduct the actual screenings. "This," said Kaback, "was a program by the community for the community."

More than 1,800 people, most of them young married couples, showed up for the first screening in May at a Bethesda synagogue. Housewives handled the paperwork, while volunteer doctors, many of them interns from Johns Hopkins Hospital, drew the blood samples which were then sent to the Kennedy Institute for analysis. Since then, nearly 6,000 more people have turned out for similar sessions at community centers and religious schools. All were asked, though not required, to pay $5 to help cover the cost of the program, which is sponsored in part by the Maryland Department of Health and Mental Hygiene. Almost all did, for the screening, even if it should lead to further testing and therapeutic abortion, is a bargain compared with the agony of having a Tay-Sachs child, to say nothing of the astronomical medical bills that accumulate before the child dies.

Chain Letter. Thus far, the screening program has produced few surprises. Ka-back's team has identified individual carriers at the rate of about one in 30. Because the gene is recessive, both parents must carry it for their children to be in danger. Even if both parents do have the trait, the chances of the child getting Tay-Sachs are one in four. So far, the program has identified four couples in which both husband and wife are carriers. They will be able to avoid the experience of two women who found out about the disease the hard way. One was seven months pregnant with her second child when she was told that her first had Tay-Sachs disease. She had to worry through the remaining two months before learning that the second child had escaped the awful inheritance. When the test revealed that her third child would have Tay-Sachs disease, she elected to have an abortion. The second mother of a Tay-Sachs child allowed herself to become pregnant again once she knew that amniotic tests could guide her decision whether to bear the child.

"Four months ago, 98% of the Jews in the Baltimore-Washington area had never even heard of Tay-Sachs disease," says Dr. Kaback. "Now, 95% know what it is." More important, a significant number are doing something about it. Not only are Baltimoreans continuing to have themselves screened for the defective gene, but, in chain-letter fashion, many of those found to carry the trait have been contacting relatives to urge that they, too, be tested.

Eventually, the Baltimore approach could be applied to other inherited hazards. Says Kaback: "There is nothing experimental about our tests. They are accurate and effective. What is experimental is the program itself. We're trying to see if we can deliver genetics -education and counseling-to a large community." As far as the Baltimore-Washington area's Jewish community is concerned, the effort is succeeding.

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