Ashkenazi Jews and Crohn's: What's the Connection?
Nov 12, 2018 Cedars-Sinai Staff
New research is helping explain why people of Ashkenazi Jewish descent develop Crohn's disease, an autoimmune inflammatory disease of the intestinal tract, at higher-than-average rates.
Scientists from Cedars-Sinai and 5 other medical centers examined the genetics of 18,745 individuals, including 5,685 Ashkenazi Jewish people.
"It has the potential to help clinicians screen and identify patients with increased risk for Crohn's disease."
Researchers compiled a catalog of genetic variants that alter the sequences of all known genes using an approach known as whole exome sequencing.
"This data resource is a genetic treasure trove that will help the research community around the world study genetic diseases," says Dr. Dermot McGovern, director of Translational Medicine at Cedars-Sinai and co-senior author of the study.
"It has the potential to help clinicians screen and identify patients with increased risk for Crohn's disease. It also provides a catalog of other heritable diseases that are found at higher frequencies in the Ashkenazi Jewish population."
Investigators examined the exomes in their sample population of Ashkenazi Jews, looking for associations and links to Crohn's disease. They found 10 variations of the NOD2 and LRRK2 exomes that are associated with increased risk for Crohn's and are more likely to occur among Ashkenazi Jews.
The study suggests that this difference in genetics may predispose the Ashkenazi population to a higher risk of Crohn's disease compared to non-Jewish people.
"These increased genetic risk factors seen in Ashkenazi populations appear to be rooted in a history of migrations, catastrophic reductions in population, and then re-population from a small number of surviving founder families over many centuries"
According to Dr. McGovern, the findings may also help doctors create better treatment plans in the future utilizing precision medicine.
These increased genetic risk factors seen in Ashkenazi populations appear to be rooted in a history of migrations, catastrophic reductions in population, and then re-population from a small number of surviving founder families over many centuries, suggests Dr. McGovern. These factors effectively concentrated genetic variations in a comparatively small population.
While the study focused on Crohn's disease, researchers also looked at several rare diseases found at higher rates among Ashkenazi Jews, including Gaucher, Canavan, and Tay-Sachs diseases.
"We now have a comprehensive understanding of the exome of the Ashkenazi Jewish population—in effect, an imprint left by history on their genetic architecture," says Dr. McGovern.