Interleukin 10 (IL‐10) gene variants and susceptibility for paediatric onset Crohn’s disease

Summary 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.