Ulcerative Colitis (cont.)

The cause of ulcerative colitis is not known. To date, there has been no convincing evidence that it is caused by infection or is contagious.

Ulcerative colitis likely involves abnormal activation of the immune system in the intestines. The immune system is composed of immune cells and the proteins that these cells produce. These cells and proteins serve to defend the body against harmful bacteria, viruses, fungi, and other foreign invaders. Activation of the immune system causes inflammation within the tissues where the activation occurs. (Inflammation is, in fact, an important mechanism of defense used by the immune system.) Normally, the immune system is activated only when the body is exposed to harmful invaders. In patients with ulcerative colitis, however, the immune system is abnormally and chronically activated in the absence of any known invader. The continued abnormal activation of the immune system causes chronic inflammation and ulceration. The susceptibility to abnormal activation of the immune system is genetically inherited. First degree relatives (brothers, sisters, children, and parents) of patients with IBD are thus more likely to develop these diseases.

In the last 1 to 2 years, there have been multiple studies using genome wide association scans investigating genetic susceptibility in ulcerative colitis. These studies have found there to be approximately 30 genes that might increase susceptibility to ulcerative colitis including immunoglobulin receptor gene FCGR2A, 5p15, 2p16, ORMDL3, ECM1, as well as regions on chromosomes 1p36, 12q15, 7q22, 22q13, and IL23R. At this early point in the research, it is still unclear how these genetic associations will be applied to treating the disease, but they might have future implications for understanding pathogenesis and creating new treatments.

Source: MedicineNet.com
http://www.medicinenet.com/ulcerative_colitis/article.htm