Although Tay-Sachs, a fatal genetic disease, has been almost eradicated from the Jewish community because of the high rate of genetic screening among Jews, a genetics expert is warning of a possible resurgence because of the increased rate of intermarriage.
The expert, Dr. Judith Willner, associate professor of human genetics and pediatrics at Mt. Sinai School of Medicine, said in an interview that the percentage of intermarried couples who have sought genetic screening at Mt. Sinai in recent years has been just 15 percent — about half the area’s intermarriage rate. Mt. Sinai has the largest genetics screening program in the New York area.
This low percentage is despite a recommendation from the American College of Obstetrics and Gynecology that all Jewish and non-Jewish couples be screened for Tay-Sachs.
“There are still doctors who do not refer such couples for screening,” Willner said.
An apparent reason for the low percentage, she said, is because the chances of a non-Jew having the Tay-Sachs gene is 1 in 300 — compared with 1 in 25 among Ashkenazi Jews. This has given non-Jews a false sense of security and they do not think of getting screened before having a child, Willner said.
The risk of a Jewish couple having a Tay-Sachs baby is 1 in 2,500; the odds of an intermarried couple having a Tay-Sachs baby is 1 in 30,000.
“People will look at these numbers and say they are not going to spend the $40 for the test,” said Willner.
She added that members of an interfaith couple should be tested together to avoid the anxiety of learning that the Jewish partner is a carrier of the Tay-Sachs gene and then having to wait as long as three weeks to learn test results from the partner.
Genetic screening has been instrumental in reducing the incidence of Tay-Sachs in babies of Jewish parents, Willner noted. In 1971, the year before Tay-Sachs screening began in the Jewish community, 50 Tay-Sachs babies were born. The figure has since dropped to the low single digits.
“That’s very impressive,” she told the fourth annual Long Island Women’s Forum last week in Woodbury, L.I. The event, which attracted 425 women from all four streams of Judaism, was coordinated by the Long Island Women’s Campaign of UJA-Federation.
“I’ve been doing genetics for 25 years and once, a year ago, I diagnosed a baby with Tay-Sachs,” Willner recalled. “It was an infant. In the back of his eyes you could see discoloration — the tell-tale sign of Tay-Sachs. I had to sit with his parents that day and tell them that this gorgeous little boy would be dead by the time he was 2 or 3. The parents of such children die two times — the day they are told [of the disease], and when the child dies.”
There is no treatment for Tay-Sachs and it is always fatal. “It is a terrible disorder and progressive,” she said. “You become blind and have uncontrollable seizures. But it doesn’t have to happen [because of genetic screening].”
Willner explained to the group that genetics testing is designed to detect abnormal genes, which she compared to a misspelled word that makes the sentence in which it was used incomprehensible. She noted that both the Association of Orthodox Jewish Congregations and the Association of Orthodox Jewish Scientists have agreed with the importance of Tay-Sachs screening and encouraged it in people looking for a mate. But because both groups are against the termination of pregnancies, they are against such screening for already-engaged couples.
On the other hand, Willner pointed out, “respected Orthodox rabbis have been interviewed and there is not unanimity on screening or abortion. Some don’t believe in it because they say it would only lead to abortion. Others say abortion is acceptable within 40 days of conception.”
She said in vitro fertilization (the artificial union of sperm and egg in a petri dish) has made it possible for a carrier couple — both of whom have the Tay-Sachs gene — to be guaranteed a Tay-Sachs-free child.
“Each cell is subsequently analyzed and only those unaffected [by the Tay-Sachs gene] are implanted” into the woman’s womb, said Willner.
Once individuals have been identified as carriers, Willner said they are encouraged to tell their cousins and siblings because they too are at risk.
“You’d be surprised at the number of couples not willing to share that information with their families and physicians,” she said. “We want to get away from the idea that someone is tainted just because they carry these genes.”
She ruled out doing Tay-Sachs screening until a person is of marriageable age because maturity is needed to understand the implications. And she said it is crucial that Sephardic Jews also be tested.
If two carriers of the Tay-Sachs gene marry, Willner said, there is a 25 percent chance that their child will have the disease, a 25 percent chance the child will not get the gene and a 50 percent chance the child will not contract the disease but will be a carrier of the Tay-Sachs gene.
At Mt. Sinai, said Willner, “we do not establish a chart on patients and insurance companies don’t get the results. I can’t guarantee that every lab handles it that way, but New York passed a law to protect individuals against employment and insurance discrimination.”
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