March 19, 2010 -- Fifteen newly identified genes may offer a better
understanding of the cause of ulcerative colitis and its ties to Crohn’s
Two new studies involving more than 23,000 people bring the total number of
genes associated with the painful disorder to nearly 30 and show at least half
of these genes are also linked to Crohn’s disease.
“It is clear from these and other data that ulcerative colitis and Crohn’s
disease share some mechanistic pathways and susceptibility genes, but that some
pathways and genes are particular to each condition,” researcher Dermot P.B.
McGovern, MD, PhD, of Cedars-Sinai Medical Center, and colleagues write in
Researchers say the discovery of these additional genes may help explain why
the symptoms and severity of ulcerative colitis vary so dramatically from
person to person. Understanding these individual differences may eventually
lead to more effective and personalized treatments.
Ulcerative colitis and Crohn’s disease are the most common forms of
inflammatory bowel disease. Ulcerative colitis usually affects only the colon
and rectum; Crohn’s disease may affect any part of the digestive tract.
Ulcerative colitis and Crohn’s disease can cause symptoms such as abdominal
pain, bloody diarrhea, and bleeding from the rectum.
Researchers say Crohn’s disease is more likely than ulcerative colitis to
run in families.
In the first study, researchers combined results from previous genetic scans
of 2,693 people with ulcerative colitis and 6,791 healthy people with a new
analysis of genetic information from another set of 2,009 people with the
disease and 1,580 healthy people.
The results highlighted 13 new genetic mutations associated with ulcerative
colitis and confirmed 14 previously identified genes associated with the
The second study identified two additional genes linked with an increased
risk of ulcerative colitis in 1,043 German people with ulcerative colitis and a
comparison group of 1,703 without the condition. Those results were then
confirmed in another group of 2,539 people with ulcerative colitis and 5,428
Researchers say about half of the known genes associated with Crohn’s
disease are shared with ulcerative colitis.
Although the findings increase the understanding of the cause of ulcerative
colitis, researchers say there is still a long way to go.
“Taken together, our findings explain less than 10% of the variance of
ulcerative colitis, and the challenge now is both to identify additional
genetic factors and to translate these advances into real benefits for
individuals with ulcerative colitis,” write McGovern and colleagues.