Interleukin 10 (IL-10) gene variants and susceptibility for paediatric onset Crohn's disease

Background A recent genome-wide association study in adult patients with ulcerative colitis (UC) has implicated the interleukin 10 (IL-10) gene as an important candidate gene. Moreover, a UC-associated single nucleotide polymorphism (SNP) rs3024405 was also significantly associated with adult Crohn's disease (CD). Aims To examine whether IL-10-CD associations extended to paediatric-onset CD. Methods We implemented the case-control design at three paediatric gastroenterology clinics in Canada. CD patients (≤20 years) were recruited along with healthy controls. DNA samples were genotyped for tag-single nucleotide polymorphisms (tag-SNPs) in the IL-10 gene. Allelic, genotype and haplotype associations with CD were studied. Results A total of 270 patients and 336 controls were studied. The mean age (±s.d.) at diagnosis was 12.1 (±3.5). There were a slightly higher proportion of male patients (56.3%). Of the five IL-10 tag-SNPs, rs2222202 (C/T) (P = 0.03) and rs1800871 (C/T) (P = 0.05) showed significant allelic associations with CD. Specific IL-10 SNPs were associated with CD disease location and/or disease behaviour. Conclusions Our gene-wide analysis replicates recent findings of associations between IL-10 and adult CD, and suggests that these associations extend to paediatric-onset CD as well.