IRF1 and systemic sclerosis: According to the criteria established for the replication analysis (genome-wide significance in the combined analysis including both discovery and replication sets, and nominal statistical significance in each disease-specific replication analysis), we identified a total of 4 genetic variants showing a pleiotropic effect in SSc and CD: two intronic variants located within IL12RB2 and STAT3, a SNP close to IRF1, and an intergenic variant at 6p21.31 located between ZBTB9 and BAK1 (Table 1).