Ashkenazi Jewish History: What Your Genetic Ancestry Results Can Tell You About Your Health
by Devin Cox, MS, CGC
Genetic testing for ancestry is more accessible and affordable than ever, and every day it is helping people crack the code on their family histories. These ancestry tests originally gained popularity as people wanted to learn more about where they came from, who their relatives were and what cultures they were tied to.
However, the field has now expanded, and some of these direct-to-consumer tests can review DNA and provide some basic information about a person’s health history. Even if people aren’t searching for health information when they take a direct-to-consumer test, their genetic ancestry might reveal clues about their likelihood to inherit certain conditions.
Such is the case for people of Eastern European descent who find out that they have Ashkenazi Jewish ancestry. This particular group of people has a history that is specifically linked with certain genetic diseases and conditions.
What is Ashkenazi Jewish ancestry?
Ashkenazi is a Jewish population that migrated from the middle east into Eastern Europe. Several of the original founders of the Ashkenazi population that migrated into Eastern Europe had mutations for genetic conditions. After they settled into Eastern Europe, this group tended to marry other individuals of their own faith and this led to these mutations becoming more concentrated within the Ashkenazi population. Because of this, there are certain “founder mutations” that are more common for people who have Ashkenazi Jewish ancestry.
So, knowing that someone has Ashkenazi Jewish ancestry can give them information about potential genetic conditions that they or their children might have.
What genetic conditions are people of Ashkenazi Jewish ancestry at risk for?
For example, there are a group of pediatric genetic conditions that are more common in this population. One of these conditions is Tay-Sachs disease, a neurodegenerative disorder. People who have 100% Ashkenazi Jewish ancestry have a 1 in 27 (3.7%) chance of being a carrier for this disorder. If two people who are carriers for this disorder have a child, each pregnancy has a 1 in 4 (25%) chance of inheriting both mutations, leading to the disorder.
Another example of a genetic condition more common in this population is hereditary breast and ovarian cancer. People who have 100% Ashkenazi Jewish ancestry have a 1 in 40 (2.5%) chance of inheriting one of the founder mutations in the BRCA1 or BRCA2 genes, which increases their risk for breast and ovarian cancers. The risk for inheriting these conditions goes down based on the amount of Ashkenazi Jewish ancestry found. For instance, someone who has 25% Ashkenazi Jewish ancestry (one grandparent) has a 1 in 160 (0.63%) chance of inheriting one of the BRCA1 or BRCA2 founder mutations.
If someone discovers that they have Ashkenazi Jewish ancestry, they should consider speaking with a genetic counselor, especially if they are thinking of having children. Prenatal genetic counselors can review that person’s family history and discuss appropriate carrier screening testing for conditions like Tay-Sachs disease. Cancer genetic counselors can review that person’s family history and discuss the potential need to test for conditions such as hereditary breast and ovarian cancer syndrome based on the individual’s family history and the amount of Ashkenazi Jewish ancestry.
To find a genetic counselor in your area, visit FindaGeneticCounselor.com.
Devin Cox, MS, CGC, is a certified genetic counselor at The University of Kansas Health System and a member of the National Society of Genetic Counselors.