IL23R and inflammatory bowel disease: Genome-wide association studies meta-analyses and replications have identified over 260 genetic risk loci for IBD, and most loci contain genetic risk variants found commonly among European ancestry populations.12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 Aside from NOD2 and IL23R with greater than 2-fold increased risk for single-risk variants (and approximately 20-fold for NOD2 mutation homozygotes), the remainder of the commonly inherited IBD risk variants individually contribute very modestly to IBD risk, with odds ratios less than 1.3 to just above 1.0 for most loci.