The IBD5 locus (MIM#606348) on chromosome 5q31 has been demonstrated to confer increased risk for inflammatory bowel disease. Controversial reports have been published about the significance of individual loci located in this region. Here we investigated the possible genetic association of inflammatory bowel diseases with C1672T of SLC22A4 and G-207C SLC22A5 alleles, and with IGR2096a_1 (rs12521868) and IGR2198a_1 (rs11739135) susceptibility variants of the IBD5 region located on chromosome 5q31.
Patients and methods: Total of 440 patients, 206 with Crohn's disease, 234 with ulcerative colitis, and 279 controls were studied by PCR-RFLP methods.
Results: Neither the C1672T, and G-207C alleles, nor the TC haplotype were found to confer risk for Crohn's disease or ulcerative colitis. By contrast, both of the minor allele frequencies of IGR2096a_1 T (48.1%) and IGR2198a_1 C (46.1%) were increased in Crohn's disease subjects as compared with the controls (38.5% and 38.4%, respectively; p<0.05). Using regression analysis adjusted to age and gender these alleles were found to confer risk for Crohn's disease (OR=1.694, 95% CI: 1.137-2.522; p=0.010 for T allele, OR=1.644, 95% CI=1.103-2.449; p=0.015 for C allele of IGRs). In UC no such associations were found.
Conclusions: Our results revealed the susceptibility nature of the examined IGR minor alleles in Hungarians, which nation differs historically from the surrounding Caucasian populations in origin of the founders of the state.