If you have someone in your family who has Crohn’s or another autoimmune disease, you are more likely to get it yourself. Studies have shown that people with Crohn’s have a specific gene variant that interacts with bacteria in the gut in an atypical and destructive way.
This gene variant causes people to be more susceptible to environmental triggers. It is not a diagnosis in itself, but works together with other factors to cause the maladaptive reaction in the immune system. They say “genetics loads the gun, but environment pulls the trigger.”
Statistics show 1 out of 5 Crohn’s sufferers may have a close relative, such as a parent, sibling or child who has the disease. It is even more likely that someone in your family has another autoimmune disease of some kind.
Twins studies show a definite genetic link, with 55% of identical twins getting the disease when the other has it. Since identical twins share the same genes, this shows that it is in fact genetic and yet must have an environmental component also.