By Elianna Miller
Many people have heard of Tay-Sachs disease, but what have
they heard? Some are aware of the connection to Jewish ancestry and the
devastation related to diagnosis. However, most don’t know about the history
and cause of the disease, or the steps the Jewish community has taken to nearly
eliminate it from our population. Community health organizations, like the
Sarnoff Center, have provided resources to make this happen.
What is Tay-Sachs Disease?
Babies born with Tay-Sachs Disease experience slow nervous
system deterioration, which diminishes cognitive functioning. This is usually
seen as the loss of motor skills, vision, hearing, and strength someone had
previously developed. Near the end of the 19th century, the
researchers Warren Tay and Bernard Sachs worked separately but both contributed
to the discovery of the disease. Sachs also noted the prevalence in Jewish
populations.
Because of the fatality, the search for a cause and a cure was on.
Fast forward to August of 1969, Drs. Okada and O'Brien found
the enzyme that babies with Tay-Sachs lack: Hexosaminidase A. It is responsible
for breaking down lipids (fat) in the brain and spinal cord. They become toxic
if not broken down, which explains the destruction of the nervous system. Tay-Sachs
is autosomal and recessive because as long as there is at least one functioning
copy of the gene, Hexosaminidase A is produced to remove toxins. The problem
arises when there are no enzyme producing copies. This discovery, along with
the fact that about 1/30 Ashkenazi Jewish people are carriers (compared to
1/300 of the rest of the population), catalyzed people to do something. The
realization of the link to Jewish ancestry led to an understanding in the
scientific community that other genetic disorders are more prevalent in other specific
populations, too.
So, Tay-Sachs is more common in Jewish populations. What does this mean?
The first community carrier screening event was held in 1971
at a synagogue in Maryland. Trained volunteers and physicians drew blood from
over 1,500 people, which revealed if they had a possibility of having a child
with Tay-Sachs. For the first time, people had knowledge about personal risk of
having affected kids. Other Jewish communities wanted to do something similar.
The number of babies born with Tay-Sachs has reduced over
90% in the last 50 years. The reduction of cases of Tay-Sachs is not due to a
cure, as there is not one yet. Carrier frequency in Jewish populations also has
not changed. It is due to people being more educated about personal risk and
taking the time to learn what they can do for prevention.
How does the Norton & Elaine Sarnoff Center for Jewish Genetics play into all of this?
The Center was founded in 1999 as an educational resource for
genetic health risks in the Chicago Jewish population. Screening began shortly
after that for only the 4 most common Jewish genetic disorders including
Tay-Sachs. That number jumped to 19, then later to about 50. Today, there are
around 80 “Jewish” disorders that we know of, and the Sarnoff Center screens
for those and about 120 pan-ethnic disorders. One out of four Ashkenazi Jewish
people are a carrier for at least one of these.
Since the beginning, we put on
community health screening events much like the one in Maryland. A presenter
would explain the importance of screening and make sure everyone went through
the informed consent process during a dinner, and before leaving they would
participate in a blood draw. However, these blood draws are no longer needed
because screening can be done with a spit kit from home.
Fun and interesting educational resources are much more easily accessible than
they once were, so even people without a background in genetics can teach
others the importance of awareness!
References:
https://www.jta.org/2017/08/11/united-states/how-the-jews-nearly-wiped-out-tay-sachs
https://www.ntsad.org/index.php/tay-sachs/history
https://www.flickr.com/photos/genomegov/30652973183/
