MDR1 gene polymorphisms are associated with ulcerative colitis in a cohort of Serbian patients with inflammatory bowel disease

BACKGROUND Inflammatory bowel disease (IBD) is a chronic disease of unknown etiology in which genetic factors contribute to development of disease. Single nucleotide polymorphisms (SNPs) in multidrug resistance 1 (MDR1) gene encoding transporter P-glycoprotein have been associated with IBD, but their role in disease susceptibility remains unclear. Therefore, the aim of this study was to investigate the association of three MDR1 polymorphisms, C1236T (rs1128503), G2677T/A (rs2032582) and C3435T (rs1045642), with Serbian IBD patients. METHODS A total of 206 IBD patients, 107 Crohn's disease (CD) and 99 ulcerative colitis (UC), and 255 healthy controls were included in the study. All subjects were genotyped using TaqMan SNP genotyping assays. Comparisons between the groups were performed using the Pearson Chi-square test. False discovery rate according to Benjamini-Hochberg procedure was applied to adjust for multiple comparisons. RESULTS Carriers of T allele of all three MDR1 SNPs were more common in UC patients compared to healthy controls, suggesting predisposing role of T allele of these SNPs in UC pathogenesis. Consistently, TT genotype of C1236T and TTT haplotype were also found more frequently in UC patients. On the other hand, C allele and CC genotype of C1236T and C3435T, as well as G allele and GG genotype of G2677T/A were more frequent in healthy subjects, implying protective role of these variants in UC. Likewise, CGC haplotype and CGC/CGC diplotype were more frequent in controls. Contrary to UC, no statistical difference was observed between CD patients and controls in any of the SNPs analyzed. CONCLUSION MDR1 gene variants and haplotypes were associated with UC in Serbian IBD patients, further supporting their potential role in susceptibility to UC.