Inflammatory Bowel Disease Gene ID'd
Gene Is Likely One of Several Linked to IBD, Researchers Say
Oct. 26, 2006 -- Scientists have spotted what they suspect is the first of
several genes tied to inflammatory bowel disease (IBD).
The gene is called IL23R. It's noted by Yale University's Judy Cho, MD, and
colleagues in Science's early online edition.
Inflammatory bowel disease includes
disease Crohn's disease and ulcerative
colitis ulcerative colitis. Its
exact cause is unknown.
About a million people in the U.S. have IBD, according to the National
Institute of Diabetes and Digestive and Kidney Diseases.
The gene discovery is "not a gene test" for IBD, and it's "not going to be
an immediate panacea" for people with IBD, Cho tells WebMD. "But we have a lot
better information, and the power of information, I think, is going to
hopefully make a difference."
For instance, the gene findings may eventually lead to new drugs to treat
"It basically says, 'OK, let's put this at the top of the list of things
that we should really work on,'" Cho says.
"Inflammatory bowel disease is an uncontrolled chronic inflammation of the
intestines," Cho tells WebMD. "As you might imagine, the inflammatory process
is very complex.
"Imagine a fire where there's all kinds of things that are contributing to
the fire," Cho says. "The power of genetics is that it identifies ... the
trigger that started the whole process."
A certain chemical pathway in the body, called the interleukin-23 pathway,
was highlighted in other IBD studies, Cho notes.
"Now the genetics says the same thing," Cho says.
Cho's team checked the DNA of nearly 1,000 people with Crohn's disease and
almost 1,000 people without either form of IBD. All participants were whites of
The scientists looked for DNA differences in the patients and the people
without IBD. Several variations of the IL23R gene -- which rules the
interleukin-23 pathway -- stood out.
In particular, people with an uncommon gene variation were two to four times
less likely to have Crohn's disease, Cho says.
"So instead of thinking about the genetics of disease, maybe you should be
thinking about the genetics of health," Cho says.
Cho and colleagues are continuing their gene studies.
"Undoubtedly, there are other genes" involved in IBD, Cho says. "We think
that there's going to likely be at least several others."
It will be important to do IBD gene studies in people of other ethnic
backgrounds, she notes.
As for new treatments, drug companies may be able to make antibodies that
block the interleukin-23 pathway.
That strategy would be "very effective at tamping down inflammation, but it
might be almost too potent," Cho says. "We have the inflammatory response to
fight off infection."
A better approach might be to mimic the protective gene variant, Cho
"You would tamp down inflammation in a way that you're not more prone to
develop infections," she says, calling the development of such drugs "a