These are rs6478109 itself, rs7848647 (the most significant IBD-associated variant in Europeans in Liu et al [4]) and rs10817678, all of which are located upstream of TNFSF15. Two of these, rs6478109 and rs7848647, are located close to the promoter of TNFSF15, in a region containing a cluster of transcription factor binding sites, active chromatin marks and enhancers, making them the leading candidates for the causal variant (S7 Fig). Here, TNFSF15 is linked to inflammatory bowel disease.