Based upon substantial enrichment identified in large-scale GWAS studies for IBD association with SNVs in the vicinity of the promoters of regulated macrophage-expressed genes (Baillie et al. 2017), we hypothesized that if they exist, regulatory variants affecting basal or inducible gene expression in monocytes differentiated in CSF1 would be prevalent in IBD families. Here, CSF1 is linked to inflammatory bowel disease.