determination of vitamin d serum levels and status of the c3435t polymorphism of multidrug resistance 1 gene in southeastern iranian patients with ulcerative colitis

background: ulcerative colitis (uc) is a multi-factorial autoimmune disease. p-glycoprotein is encoded by the multidrug resistance 1 (mdr1) gene. the c3435t polymorphism in the mdr1 gene is correlated with low p-glycoprotein expression. additionally, vitamin d has regulatory effects on the immune system. the aim of our study was to determine the association between the c3435t mdr1 polymorphism and uc and to detect the vitamin d serum levels in patients with uc. methods: one hundred healthy controls and 85 patients with uc were evaluated. polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) was used to detect the c3435t mdr1 polymorphisms. serum levels of vitamin d were measured by enzyme-linked immunosorbent assay (elisa). the research was performed in kerman, iran, from 2011 to 2013. results: we could not find any association between the c3435t mdr1 polymorphism and susceptibility to uc. there was a significant decrease in serum levels of vitamin d in patients with uc compared with healthy controls ( p <0.001). conclusion: controversies regarding the association between the c3435t mdr1 polymorphism with uc have been reported in different populations. the difference between our results and others may be attributed to the heterogeneity of the iranian population and the sample size. additionally, our data indicated that uc might be correlated with vitamin d insufficiency. therefore, the administration of vitamin d might be suggested as a valuable treatment for patients with uc.