Association of the interleukin-23 receptor gene variant rs11209026 with Crohn's disease in German children

AIM

Genome-wide association studies have described variants within the interleukin-23 receptor (IL23R) locus to be associated with Crohn's disease (CD) and ulcerative colitis (UC). We investigated the association of rs11209026 (p.Arg381Gln) and rs7517847 (c.799-3588T>G) into German paediatric inflammatory bowel disease (IBD) patients and analysed IL23R transcriptional activity in colonic tissues.

METHODS

The rs11209026 and rs7517847 nucleotide substitutions were determined in 353 German children with IBD (221 CD, 132 UC) and 253 controls using pre-designed TaqMan((R)) SNP genotyping assays. In selected IBD patients and controls, IL23R mRNA expression was measured using real-time PCR.

RESULTS

The prevalence of the rs11209026 A allele was lower in CD patients, but not in UC patients, when compared with controls (1.8% vs 7.1%, p < 0.01). The rs7517847 variant, in contrast, was associated neither with CD nor with UC. IL23R expression was variable in IBD patients compared with controls without significant overexpression or downregulation.

CONCLUSION

Our study provides additional support for the strong protection of the rs11209026 (p.Arg381Gln) variant against paediatric CD. IL23R was expressed in both CD and UC with a great variability. However, expression levels showed no significant association with the disease.