No evidence for involvement of IL-4R and CD11B from the IBD1 region and STAT6 in the IBD2 region in Crohn's disease

Linkage studies have identified the inflammatory bowel disease (IBD) 1 locus on chromosome 16 and the IBD2 locus on chromosome 12 to be involved in Crohn's disease. NOD2/CARD15 was identified as the gene of interest within the IBD1 region. However, linkage to this region could not be explained by NOD2/ CARD15 alone. Here we set out to assess the association of additional candidate genes from the IBD1 and IBD2 loci with Crohn's disease using transmission disequilibrium testing in patient - parent triads. No significant association was observed with genetic variants in the genes coding for interleukin-4 receptor gene (IL-4R), CD11B and signal transducer and activator of transcription type 6 (STAT6). Results for IL-4R were not affected by exclusion of all families carrying one of three risk alleles in NOD2. From this we conclude that IL-4R and CD11B in the IBD1 region and STAT6 in the IBD2 region are not involved in Crohn's disease in this Dutch cohort.