Effect of gene promoter genotypes in patients with ulcerative colitis.

A complex interaction of genetic and environmental factors is closely associated with the development of inflammatory bowel disease. Previous studies reported that the expression of the regulated upon activation, normal T-cell expressed and secreted () gene is enhanced in the colonic mucosa of ulcerative colitis (UC). Quantitative differences in gene expression among numerous promoter genotypes have also been reported. The aim of the present study was to clarify the effect of promoter polymorphism on the risk of UC, including its clinical phenotypes. A total of 150 UC patients and 372 healthy control (HC) subjects participated in the study. The UC patients were classified by disease behavior, severity and extent of disease. Restriction fragment length polymorphism analysis was performed for polymorphisms at -28 C/G in the gene promoter region. Although no significant difference of the promoter genotype distribution was observed between the HC and UC groups, the G/G genotype was significantly higher among female (OR=3.95, 95% CI=1.22-12.82, P=0.03), non-steroid dependent (OR=3.37, 95% CI=1.16-9.85, P=0.03) and non-refractory (OR=3.76, 95% CI=1.29-10.98, P=0.02) UC patients. The G carrier was also found to be associated with an increased risk of rectal colitis (OR=2.21, 95% CI=1.12-4.39, P=0.03). The data indicate that the polymorphism of the promoter is not directly associated with the susceptibility to UC, but the -28 G allele is associated with female UC patients and mild clinical phenotypes of UC including non-steroid dependency, non-refractory and rectal colitis.