ABSTRACT
P-glycoprotein, the product of MDR1 [multi drug resistance] gene, is a trans membrane efflux pump, transferring drugs and toxins from intracellular to extracellular domains. It acts as a protective barrier to keep toxins out of the body by excreting them into the bile, urine and intestinal lumen. In the human gastrointestinal tract, P-glycoprotein is found in high concentrations on the epithelial cells of colon and small intestine. MDR1 gene polymorphism such as C3435T is associated with lower Pglycoprotein expression, thus it is suggested to have an association with ulcerative colitis. We tried to determine the frequency of C3435T polymorphism of MDR1 gene in Iranian patients with ulcerative colitis and compare it with healthy control population. In this case-control designed study, we assessed the C3435T polymorphism of MDR1 gene, in 150 ulcerative colitis patients and 150 sex- and ethnicity-matched healthy controls, who were visited at a teaching hospital during a one year period.[2002-2003]. The extracted leukocyte DNA was amplified by polymerase chain reaction [PCR] with specific primers, and C3435T polymorphism was detected by RFLP method. The mean age of patients was 40.1+/-13.9 years [14-74] and of controls was 40.7+/-14.0 years [16-79]. The frequency of C3435T allele was significantly higher in ulcerative colitis patients compared with controls [OR=1.58, 95% CI= 1.13 - 2.22, p<0.008]. The frequency of C/T genotype was also significantly higher in patients with ulcerative colitis [OR=1.67, 95% CI=1.06-2.64, p<0.028]. This study suggests that the higher frequency of 3435T allele has an association with ulcerative colitis in Iranian population as previously reported in western countries