Ashkenazi Jewish heritage and genetic counseling Advanced Tele-genetic Counseling AT-GC

When I was in graduate school, I saw a patient with my supervisor that I will never forget. We walked into a patient room to see a young couple and an older woman. The patient was in his early 30s. He had been waking up for 6 months with night sweats and had been having stomach pain. He finally went into the doctor and was diagnosed with stage IV pancreatic cancer. When he came to see genetics, he was hoping to test positive for a BRCA gene mutation so that he could enter a clinical trial. As we were talking, his wife reported that they had been trying to conceive a child and she was possibly pregnant with their first. His mother reported that they were of Ashkenazi Jewish heritage, and after completion of a family tree it seemed possible that he did have a BRCA gene mutation. Unfortunately, I do not know what happened to that family or if he did test positive for a BRCA gene mutation. But I realized after seeing that patient how important it is to have genetic screening if you are of Ashkenazi Jewish heritage and have a family history of cancer.

Why are individuals of Ashkenazi Jewish heritage at an increased risk to have certain gene mutations that can cause diseases? Ashkenazi Jews are Jews of Eastern European origins and account for approximately 80% of all Jews in the world. Recent population studies of Ashkenazi Jews have used genetic markers to connect this group to the ancient Middle East. But more importantly from a genetic standpoint, the Ashkenazi Jewish population is unique in that this population began with a limited number of founders, and as the population grew, they did not procreate with anyone outside of their population. In addition, those within the Ashkenazi Jewish population that did procreate were from a small fraction of wealthier people within the community, which makes the gene pool even smaller.

Today, there are many “founder mutations” or gene mutations that date back to the original group of Ashkenazi Jews, that have been passed down through the generations. For example, there are three BRCA founder gene mutations that those of Ashkenazi Jewish descent should get screened for if they have a strong family history of breast and ovarian cancer.

In addition, there are many recessive genetic conditions in which both partners have to be carriers for the disease in order for there to be a ¼ risk to a pregnancy, that have an increased carrier rate in the Ashkenazi Jewish population. Each person of Ashkenazi Jewish heritage has a 1 in 4 chance or 25% chance of being a carrier for one of the Jewish genetic disorders. Most of these conditions are fatal and very debilitating. For example, Tay Sachs disease is a recessive condition that progressively damages the nerve cells in the brain and spinal cord, ultimately ending in death in early childhood. Another disease of increased risk for Ashkenazi Jews is Gaucher disease, which inhibits production of an enzyme needed to break down a fatty substance into a sugar. This causes damage to the tissues and organs. There are three different types of Gaucher disease.

For those of Ashkenazi Jewish heritage, it is recommended to meet with a genetic counselor to get genetic screening. If you have a family history of cancer, it may be recommended to have cancer genetic testing. For those who are interested in knowing their risks of being carriers of a genetic disease prior to conceiving, it is recommended to pursue carrier screening, which can be a screening test for as little as a few genetic conditions to hundreds of genetic conditions to determine if you are a carrier. If you and your partner are identified as a carrier of the same genetic condition, there are options such as in vitro fertilization and diagnostic testing to help you decide the best way to start your family.

Please contact AT-GC to meet with a genetic counselor if you are of Ashkenazi Jewish heritage and are interested in knowing your risks.

Resources:

http://hugr.huji.ac.il/AshkenaziJews.aspx

https://www.juf.org/cjg/disorders-on-the-panel.aspx

https://medlineplus.gov/genetics/condition/gaucher-disease/#causes

https://medlineplus.gov/genetics/condition/tay-sachs-disease/

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