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MICHAEL KABACK ’59, DEVELOPER OF A SCREENING TEST FOR TAY-SACHS
DISEASE, IS ELECTED TO JOHNS HOPKINS UNIVERSITY SOCIETY OF SCHOLARS
In the early ’70s, there were 100 children per
year afflicted with Tay-Sachs disease in North America, 85 of whom
were of Eastern European (Ashkenazi) Jewish ancestry. By the beginning
of the 21st century, there were only one or two yearly cases among
Jewish youth.
This dramatic decrease is due in large part to the
efforts of Michael Kaback ’59, a professor of pediatrics and
reproductive medicine at the University of California, San Diego,
who was recently elected to the prestigious Johns Hopkins University
Society of Scholars. Renowned worldwide as an expert on the treatment
and comprehension of Tay-Sachs disease—a fatal genetic disorder
in which harmful quantities of a fatty substance build up in tissues
and nerve cells in the brain—Kaback developed a test to detect
carriers of the Tay-Sachs gene.
Kaback first encountered the disease and its victims
as a resident at Hopkins in the late ’60s. He was researching
human genetic disorders, and had devised a way to test a fetus’
probability of developing such a disorder while in utero, using
amniotic fluid. In 1969 he became close with the family of a 16-month-old
Tay-Sachs patient at Hopkins. Because the disease causes such symptoms
as blindness, dementia, seizures, and paralysis, the child would
most likely be in a chronic vegetative state by age two or three.
“It’s a drain on a family’s resources and emotions,”
Kaback says. “Each day is worse than the day before.”
Around this time, the 10-month-old son of a Hopkins
pediatric intern was also diagnosed with Tay-Sachs. The mother was
seven months pregnant and now feared that her second child would
also be affected. Kaback tested the infant girl shortly after her
birth; she was found to be free of disease, and her parents, so
mired in anxiety and grief for the past few months, could finally
rejoice. Kaback felt that no family should ever be forced to endure
this harrowing experience again.
In 1970, he partnered with visiting scientist John
O’Brien from the University of California, who had the previous
year determined the biochemical cause of Tay-Sachs (insufficient
activity of an enzyme called beta-hexosaminidase, or Hex-A).
Their goal was to create a simple, accurate blood test that would
detect the disease gene in adults and the presence of the disease
in early fetuses. Thanks to O’Brien’s research, they
knew that carriers had less Hex-A in their body fluid and cells
than non-carriers, and babies with Tay-Sachs had a complete absence
of the enzyme. Because a defined ethnic origin was a factor in the
occurrence of Tay-Sachs, Kaback and O’Brien hoped that young
Jewish adults could be screened to identify carriers; at-risk couples
would then have the option of genetic counseling, pregnancy monitoring,
and carrying to term only unaffected fetuses.
Kaback set out to educate the Jewish population about
Tay-Sachs, beginning with the Baltimore-Washington area. “It
was important not to scare people unnecessarily,” he says.
“This wasn’t an epidemic—only one in 3,000 Jewish
children carried the disease. We just wanted to give them sufficient
information so they could make an informed decision.” The
educational efforts involved rabbinical leaders, social service
organizations, the Johns Hopkins School of Public Health, and many
others. Studies were conducted to gauge the Jewish community’s
attitudes toward genetic diseases and the ethical and moral issues
surrounding the screening. Press conferences were organized, and
the effort was featured in Time and Newsweek.
In May 1971, 1,800 young Jewish adults in Bethesda,
Md., participated in the first-ever community-based Tay-Sachs screening.
Within two years, similar screenings were conducted in cities across
North America, and California began the first statewide program
in 1973. The National
Tay-Sachs Disease and Allied Disorders Association (NTSAD) has
supported the establishment of an international center in San Diego
to annually survey worldwide programs in Tay-Sachs screening and
prevention and perform quality control assessments of all laboratories
involved in screening. This program has also served as a model for
the prevention of other genetic diseases in different populations,
such as beta-thalassemia in Mediterranean children and cystic fibrosis
in Caucasians. “It has implications for many other disorders
now that genome sciences are aiding in the identification of many
disease genes,” says Kaback.
Although there is still no cure, the incidence of
Tay-Sachs in Ashkenazi Jewish families has been reduced by 99 percent.
“This demonstrates how one can really have an impact on disease,”
says Kaback.
—Brenna McBride
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