This functional genomics screen has provided evidence that genes in four IBD loci (PTGIR, ZBTB40, SLC39A11 and NFKB1) are involved in controlling the expression levels of S100A8 and S100A9, the two subunits of CP, an important IBD biomarker for monitoring disease severity [15,16]. The gene discussed is PTGIR; the disease is inflammatory bowel disease.