Gene Research and Crohn's
The first gene for conferring susceptibility to inflammatory bowel disease (IBD) has been identified.
Charles O. Elson, M.D., Chairperson of CCFA's National Scientific Advisory Committee (NSAC) and others,
announced this break through on May 21 in Atlanta, Georgia, the site of Digestive Disease Week (DDW).
A team of IBD researchers led by Drs. Judy Cho and Gabriel Nunez discovered the first gene that
increases susceptibility for Crohn’s disease. Dr. Cho is assistant professor of medicine and a
researcher in the Martin Boyer Laboratories at the University of Chicago. Dr. Gabrial Nunez is
assistant professor of pathology at the University of Michigan. An independent research team in
France, led by Drs. Jean-Pierre Hugot and Gilles Thomas, studying a different group of patients,
has also identified the same gene, known as Nod2. Both teams published their findings in the May 31
issue of Nature, a prestigious journal. The researchers found a mutation in Nod2. A similar gene was
known to help plants resist bacterial infection. This finding connects the disease with the innate
immune system, the body's first line of defense against invading bacteria. Nod2 encodes a protein
that helps the innate immune system recognize and respond to lipopolysaccharides (LPS), a component
of some types of bacteria. In the mutated form of Nod2, about three percent of this protein is missing,
which reduces the ability of Nod2 to recognize LPS and respond to bacterial invaders.
Other studies have suggested that a breach in this first line of defense triggers the inflammatory response in IBD, and the mutated form of Nod2 may be the link to other 'breaches' or weaknesses. "We have long suspected that both genetics and the environment played a role in inflammatory bowel disease," explains Dr. Cho. "This finally allows us to begin to understand how they work together to cause this disease."
Reference: "Under the Microscope: Research News Bulletin from the Crohn’s & Colitis Foundation of America" Summer 2001