Familial inflammatory bowel disease - heredity or environment?

Abstract

There are clear clinical and pathologic distinctions between most cases of ulcerative colitis and most cases of Crohn's disease. These differences cannot be dismissed when considering possible causes but neither is it possible to ignore the overlapping genetic background. In favor of the explanation of overlapping genotypes is the association which both diseases have with ankylosing spondylitis. Study of the families of patients with inflammatory bowel disease (IBD) leaves no doubt that ulcerative colitis and Crohn's disease are closely associated. This association within families may be due to a common environmental etiology but more probably it is due to a shared genetic background. The pattern is in keeping with that expected if both conditions have a polygenic basis. The answer to the question 'Familial inflammatory bowel disease, heredity or environment?' is undoubtedly that both are important. When the cause or causes of IBD finally become known it is likely that genetically determined responses will be seen to be of major importance in explaining the individual susceptibility to IBD. This critical review cites 73 references.