IRF5 and systemic lupus erythematosus: A subsequent study by Sigurdsson et al. [130] identified two IRF5 polymorphisms independently and strongly associated with SLE: a 5 bp CGGGG insertion located 64 base pairs upstream of IRF5 exon 1a (P = 4.6 × 10−9) and a SNP (rs10488631) downstream of the IRF5 gene (P = 9.4 × 10−10).