Work remains on Tay-Sachs and other Ashkenazi genetic disorders – J.

In 1976, a letter to the editor thanked this publication for its coverage of Tay-Sachs genetic disease and for regularly promoting opportunities to get tested.

Back then, Tay-Sachs remained a scourge in the Jewish community. Since then, in a victory of community willpower over genetic fate, a concerted push for early testing has virtually eradicated the disease – reducing the number of Ashkenazi children born with Tay-Sachs from 60 per year to 3 to 5 per year.

But while the incidence of Tay-Sachs has declined among Ashkenazi Jews, a variety of genetic disorders still threaten the community, necessitating genetic screening.

Estie Rose
Estie Rose

“We need to plan and be proactive,” said Estie Rose, a genetic counselor at JScreen, an Atlanta-based nonprofit that provides testing and education.

In 2008, the US Senate designated September as Tay-Sachs Awareness Month, but Tay-Sachs is just one of the genetic diseases for which Ashkenazi Jews are more likely to carry a recessive gene. (A recessive gene, unlike a dominant one, is only expressed if inherited from both parents.)

About 75 percent of people of Ashkenazi Jewish heritage carry a recessive gene for at least one of several genetic disorders, according to Rose. In addition to Tay-Sachs, the most common include Gaucher disease, cystic fibrosis, familial dysautonomia, and Canavan disease. (According to the Jewish Genetic Disease Consortium, there are also several genetic diseases that are more common among Sephardic Jews.) One in 30 Ashkenazi Jews carries the gene for Tay-Sachs, while in the general population 1 in 300 is a carrier (the number is also contributed those of Cajun ancestry high).

While a recessive gene does no harm, a child with Tay-Sachs is more likely to be born to a couple who are both Ashkenazi Jews.

“It’s really only a problem if the person you’re having a child with has the same gene,” explained Mary Norton, MD and professor of perinatal medicine and genetics at the University of California, San Francisco.

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The reason Ashkenazi people are more likely to carry the Tay-Sachs gene is intertwined with the many catastrophes in the history of the Jewish people. “Think of the Crusades; think of the Holocaust; Think of the Spanish Inquisition,” Rose said. “The size of the community shrank, then it grew again.”

For genetics, such circumstances are exemplary for a population bottleneck and the founder effect. In layman’s terms, many Jews were killed at various times in history, leaving a smaller pool of genes to replenish the population. Also, Jews in Europe were endogamous, meaning they tended to marry other Jews.

“The mutations get copied and pasted over and over again,” Rose said.

Tay-Sachs was discovered towards the end of the 19th century, and even then its prevalence among Ashkenazi Jews was noted.

The most common form becomes apparent in infants around 6 months of age. Symptoms include decreased vision and an exaggerated startle response, progressing to slow growth, listlessness, neural degeneration, and seizures by age 2 years, with death occurring by age 5 years. The disease cannot be cured.

A carrier of a genetic disorder cannot have a family history of the disease or have the disease themselves. Pregnancy is often the first time many people are tested to determine if they are carriers of a range of genetic disorders. Some are not tested at all.

JScreen’s mission is to encourage people not to wait until pregnancy to get tested.

That’s what Rose did and it changed her life. During the study, she and her partner were tested to determine what genetic disorders they carried. It turned out that they were both carriers of cystic fibrosis, a life-threatening disease. If she had had children with her then-partner, they could have faced some difficult decisions.

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“We decided to break up and avoid all of those things,” she said.

Today, as a genetic counselor, Rose helps couples consider their options when faced with similar scenarios. She said JScreen tests for 225 diseases and works closely with the primary health care provider and genetic counselors.

“I can serve my own community, which is very important to me,” she said. “Unfortunately, the Jewish community faces many genetic health problems.”

About 75 percent of individuals of Ashkenazi Jewish heritage carry a recessive gene for at least one of several genetic disorders.

Rose said when a pregnant couple discovers they both carry the same disease gene, the next step is to test the fetus. If the fetus has the disorder, the couple must decide whether or not to carry the baby to term. It’s even better to do the test before you get pregnant, Rose said, “If there’s a problem, they have more options.”

The couple can explore IVF (which allows each embryo to be tested before implantation) or egg donation, or they can choose not to have children or even go their separate ways, as Rose and her then-partner did.

Sophia Pesotchinsky advocates pre-pregnancy testing Their daughter Vera, 49, has Late Onset Tay-Sachs, a rare form of the disease.

The Pesotchinskys arrived in the Bay Area from Russia in 1976. Vera later developed motor problems which turned out to be the first signs of LOTS. Sophia was never tested to be a carrier, either in Russia or here in the US when she was considering having more children. It’s a huge oversight, she said.

“When people come from another country, they need to be asked, ‘Have you had this test?'” she said.

This is especially true for people who come from the former Soviet Union. “Very often they didn’t know that they had Jewish roots,” she emphasized.

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Sophia said it took more than a decade to diagnose Vera (along the way, Sophia was told that her daughter’s issues, which ranged from slander to “clumsiness,” stemmed from an overbearing immigrant mother). Vera, who earned an MBA from Santa Clara University and a BA from Wellesley College, is currently in a wheelchair and cannot live alone, but mother and daughter are committed to helping patients through the National Tay-Sachs and Allied Diseases Association.

JScreen isn’t the only Jewish organization trying to get people screened early.

New York-based company Dor Yeshorim screens potential couples in the Orthodox community by testing for over 50 diseases. According to their latest quarterly report, out of more than 9,000 people who have used the service, 120 have been found to be genetically “incompatible.”

Like JScreen, Dor Yeshorim advises people to get tested well in advance of pregnancy. “When a match is suggested, it’s time for a compatibility check. Dor Yeshorim, Rabbanim and experienced Shadchanim urge everyone to check compatibility before a couple or parents meet to avoid unnecessary heartache!” says the site.

To this end, Dor Yeshorim often tests in Orthodox schools. JScreen is working with Hillel and Birthright, Rose said.

Advances mean genetic testing, once reserved for Ashkenazi Jews, is now accessible to the general population, further reducing the likelihood of children being born with a condition like Tay-Sachs.

Tests used to cover only about 25 gene disorders, but hundreds can now be identified.

Rose said it’s important to test regardless of ethnicity. While Ashkenazi Jews have their own risks, other ethnic groups have their own. You never know what a test result will bring, Rose noted.

“We all have things that we don’t know about our family history,” she said.

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