the causes 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 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 systems 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.
what causes ulcerative colitis?