Prof. studies Crohn’s disease

A Yale researcher has helped shed light on the role genes play in Crohn’s disease, a serious and relatively common disorder that affects the digestive tract.

The Inflammatory Bowel Disease Genetics Research Consortium, a group of researchers from the United States and Canada, reported in the online Science Express on Thursday that mutations in a particular gene are associated with Crohn’s disease. School of Medicine professor Judy Cho, a senior author of the study, was the principal investigator of IBDGRC’s data coordinating center and the chair of the steering committee.

The National Institutes of Health estimates that as many as 500,000 Americans have Crohn’s disease, a chronic disorder that causes inflammation of the digestive tract. Cho said the group compared the genomes of patients with the disease to the genomes of healthy individuals in order to search for possible genetic causes. It identified a mutation that alters the IL-23 receptor, which is involved in an inflammatory response associated with Crohn’s.

“We compared the genes of these two groups and found that there were three significant differences between the patients and control,” Cho said. “Two were the previously identified mutations in a gene called CARD15. The other was a completely new gene in IL-23 receptor.”

The researchers also found a second mutation in the IL-23 receptor that appears to confer strong protection against the disease, Cho said. By studying what this genetic variation does to suppress the onset of Crohn’s, she said, scientists might be able to find a cure for inflammatory bowel disease.

“People with this genetic variation are two to four [times] less likely to develop Crohn’s disease,” Cho said. “It’s nature’s way of telling you what can be done to cure IBD.”

Crohn’s disease is one of the two forms of inflammatory bowel disease.

Jonathan Braun, chair of national scientific advisory committee of the Crohn’s and Colitis Foundation of America, said flare-ups can be fatal without sophisticated medical care. Braun said the disease can also bar a person from conducting day-to-day activities like going to school.

According to the group, persons who have close relatives with IBD are ten times more likely than the general population to develop Crohn’s disease. It is especially common among certain ethnic groups, and these two factors have pointed scientists toward genetic influences behind Crohn’s disease.

Past research found that two mutations in the CARD15 gene are twice as likely to be found in Crohn’s disease patients as in the general population, but the two mutations alone do not account for all of the genetic risk in Crohn’s disease.

The IBDGRC consortium is funded by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institute of Health.

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