Although most people with European ancestry are pretty genetically similar, some sub-groups like Ashkenazi Jews have distinct genetic characteristics that carry important implications for health. For instance, people with Ashkenazi ancestry have higher rates of numerous rare genetic disorders like Tay-Sachs disease and are at increased risk for certain multi-gene conditions like Crohn’s disease.
The exact cause of Crohn’s disease isn’t known, but this inflammatory bowel disease may result from a case of mistaken identity — the immune system mounts a reaction to an invader and ends up attacking the body’s own cells, too. At least 12 genetic factors have been associated with Crohn’s disease in Europeans. Although researchers don’t know why people with Ashkenazi ancestry are two to four times more likely to develop Crohn’s disease, they suspect that the genetic “uniqueness” of this group may have something to do with it.
To investigate this intriguing idea, a research team led by scientists at Columbia University and Mount Sinai carried out a study looking at nearly 2,000 people with Crohn’s disease and roughly 4,500 people without it, all of Ashkenazi descent. The results, published in PLoS Genetics earlier this year, replicate previously reported associations for people of European descent and also identify novel factors specific to those with Ashkenazi ancestry.
In the new study by lead author Eimear Kenny, individuals with the C version of rs11229030 and the G version of rs7705924 had slightly higher odds of developing Crohn’s disease. Two other factors seemed to be protective. People with the T version of rs6545946 and the G version of rs12677663 had slightly lower odds of developing Crohn’s disease. More research is needed to understand how these genetic variants influence the biology of the disease.
These new findings confirm that genetics likely has something to do with the higher rates of Crohn’s disease in people with Ashkenazi ancestry. All of the newly discovered factors appeared to be specific to Ashkenazi ancestry as they weren’t found in previous studies carried out with broader European study groups.
May is Jewish American Heritage Month. Read about the “uniqueness” of Ashkenazi Jewish ancestry and how it’s important for health. Read more about Jewish ancestry in guest posts by 23andMe’s Ancestry Ambassadors, Tim Janzen, CeCe Moore and Andrea Badger.