Identification of new genetic markers for ulcerative colitis


An international consortium of researchers have identified genetic markers associated with the risk of ulcerative colitis. The findings, pre-published in the online issue of 4 January 2009 the journal Nature Genetics, allow researchers to better understand the biological mechanisms involved in this disease. Thus, they may eventually develop new treatments that specifically target.

"By identifying specific genes that cause ulcerative colitis, we have an initial overview of the causes of this debilitating disease and evidence to improve the diagnosis and treatment," says Dr. Rioux, one of the main researchers in this study.

Ulcerative colitis is a chronic and recurring problem that causes inflammation and ulceration of the rectum and large intestine. Among its most common symptoms include diarrhea (often bloody) and abdominal pain. Ulcerative colitis and Crohn's disease, another disorder gastrointestinal inflammation, are the two main forms of inflammatory bowel disease (IBD).

"Ulcerative colitis and Crohn's disease are chronic problems affecting the lives of patients every day," explains lead author of the study, Dr. Richard H. Duerr, associate professor of medicine and human genetics at the Faculty of Medicine and the School of Graduate Studies in Public Health from the University of Pittsburg. Most often, IBD is diagnosed in adolescents or young adults. Usually, patients do not die, but those who suffer from IBD living with debilitating symptoms during the most productive years of their lives. "

Because IBD tends to be inherited, researchers have long thought that genetic factors are involved. The recently developed technology has allowed for systematic research in the whole genome of DNA markers associated with common diseases in humans. The discovery of more than 30 genetic risk factors for Crohn's disease is one of the most important examples of this new era in the field of research.

If some genetic factors associated with Crohn's disease also predispose people with ulcerative colitis, the specific markers of ulcerative colitis were identified. To do this, researchers conducted a study throughout the genome, involving hundreds of thousands of genetic markers using DNA samples taken from 1 052 people with ulcerative colitis and background information of 2 571 control subjects, all of European descent and living in North America.

It was found that there were highly significant associations between genetic markers on chromosomes 1p36 and 12q15 and ulcerative colitis. Evidence of these associations also replicating in independent samples of subjects of European descent from North America and southern Italy. Among the neighboring genes may play a role in ulcerative colitis include the ring finger protein 186 (RNF186), the OTU domain containing 3 (OTUD3) and phospholipase A2, group IIE (PLA2G2E) - genes that are located on chromosome 1p36, and interferon gamma gene (IFNG), interleukin 26 (IL26) and interleukin 22 (IL22) on chromosome 12q15, which have an important role in inflammation.

The RNF186 and OTUD3 belong to the family of genes involved in the recycling of proteins and various cellular processes. The study also identified very convincing associations between ulcerative colitis and genetic markers on chromosome 7q31 gene in the laminin beta 1 (LAMB1) or near, belongs to a family of genes that are known to in health and disease of the intestines. It also confirmed the previously identified associations between ulcerative colitis and genetic variants in the gene receptor for interleukin 23 (IL23R) on chromosome 1p31 and the major histocompatibility complex on chromosome 6p21.

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