C3435T Polymorphism of the ABCB1/MDR1 gene encoding P-glycoprotein in patients with inflammatory bowel disease in a Polish population

Inflammatory bowel disease (IBD) belongs to the group of chronic diseases of the gastrointestinal tract, prevalence of which is increasing in the Polish population. The two main clinical types of IBD are ulcerative colitis (UC) and Crohn’s disease (CD). The expression level of the ABCB1/MDR1 gene which encodes P-glycoprotein seems to be of great prognostic relevance while evaluating patients’ susceptibility to UC or CD. One of the most significant ABCB1/MDR1 gene mutations is the C3435T polymorphism. A decreased expression of the ABCB1/MDR1 gene and lower P-glycoprotein activity has been associated with the 3435T variant. The aim of the study was to evaluate the C3435T polymorphism in the IBD patients and to investigate a possible correlation with disease susceptibility. The study was performed on 108 patients with IBD and on 137 healthy individuals. All the participants were of Caucasian origin and came from central Poland. The C3435T polymorphism was analyzed by using the PCR-RFLP method. Our results showed that ORs for IBD development (including UC and CD) were elevated in individuals both with the 3435CC genotype and the 3435C allele. The differences in genotype and allele frequencies were not significant. The C3435T polymorphism of the ABCB1/MDR1 gene is not a risk factor for IBD, including UC and CD, in the population coming from central Poland.