IRF1 and systemic sclerosis: Finally, we also evaluated the connectivity at the protein interaction level among the genetic risk loci shared between SSc and CD, including genes whose expression levels were affected by the pleiotopic polymorphisms identified in our study, that is IRF1, SLC22A5, STAT3, IL12RB2 and TAPBP, as well as loci associated in previous studies with both SSc and CD, including STAT4, TYK2, IRF8, GSDMA and IKZF3. GSDMA and IKZF3 belong to the same LD block, however GSDMA has been set as the most probable candidate gene of this locus in SSc and IKZF3 for CD41,42.