Background: Recent genome-wide association studies in Caucasian populations identified IL23R and ATG16L1 as susceptibility genes to Crohn's disease (CD). We tested 5 IL23R single nucleotide polymorphisms (SNPs) and 12 ATG16L1 SNPs in Korean patients to determine whether these genes are associated with susceptibility to CD in a non-Caucasian population.
Methods: We analyzed 5 IL23R SNPs and 12 ATG16L1 SNPs in 380 patients with CD and 380 healthy controls.
Results: Two IL23R gene variants, an intronic SNP rs1004819 and intergenic SNP rs1495465, showed significant associations with CD; the adjusted odds ratio (aOR) for rs1004819 was 1.822 (95% confidence interval [CI] = 1.164-2.852, P = 0.009) and aOR for rs1495965 was 1.650 (95% CI = 1.102-2.471, P = 0.015). The genotype-phenotype analysis showed subphenotype specificity to stricturing and penetrating behaviors. On the other hand, none of the 12 ATG16L1 SNPs showed any positive association with CD in Koreans. The contribution of IL23R variants in Korean CD patients overall is low in comparison with studies of Caucasian.
Conclusions: Our data in Koreans support the previous Caucasian reports of an association of the IL23R gene with CD.