Doctors don't know what causes Crohn’s disease. You may get it when the body’s immune system
has an abnormal response to normal bacteria in your intestine. Other kinds of bacteria and viruses may also play a role in causing the disease.
Crohn’s disease can run in families. Your chances of getting it are higher if a close family member has it. People of Eastern European (Ashkenazi) Jewish family background may have a higher chance of getting Crohn’s disease. Smoking
also puts you at a higher risk for the disease.
--it seems to have more to do with Northern European than Jewish ancestry (I have family with it)...hence the lucky Ashkenazi get sucked in along with the rest of the pale. They also get to be the most prevalent sufferers of Tay-Sachs Disease (if you're looking for a focused disease) and have a high incidence of cystic fibrosis. Fun don't stop.