A study by Dr. Marcel Behr, of the Research Institute of the MUHC and McGill Universit, seems to come one step further towards a possible understanding of what causes Crohn's disease.
According to a synopsis in Science Daily 25% of Crohn's patients have a mutation in what is called the NOD2 gene. (Yes, isn't it great to be a mutant - where are the other X-Men?) What has not been understood is what this gene does and how a change to it could cause Crohn's.
This new study shows that the NOD2 gene allows cells to recognize harmful bacteria and trigger an immune response. The gene in particular identifies "N-glycolyl-MDP, which is only found in a specific family of bacteria called mycobacteria." Ah, I see your ears perking up. Mycobacteria has been implicated in Johnne's disease in cattle and long suspected to be a trigger for Crohn's disease.
Here is a quote from Dr. Behr that sums up the findings:
"Now that we have a better understanding of the normal role of NOD2, we think that a mutation in this gene prevents mycobacteria from being properly recognized by the immune system," explained Dr. Behr. "If mycobacteria are not recognized, the body cannot effectively fight them off and then becomes persistently infected."
