BLK and systemic lupus erythematosus: We therefore investigated whether there were any differences in disease duration between the three genotypes in STAT4, IRF5, TNIP1 and BLK. There were no differences in disease duration between patients homozygous for the risk allele (minor allele), heterozygous or homozygous for the non-risk allele (major allele) for STAT4, IRF5, TNIP1 or BLK when comparing all SLE patients or LN patients alone (Table S4).