STAT4 and systemic lupus erythematosus: STAT4 single nucleotide polymorphisms (SNPs) are known to be associated with an increased risk of autoimmune diseases, such as systemic lupus erythematosus (SLE), primary Sjogren’s syndrome (pSS), rheumatoid arthritis (RA), or thyroid disease [12], so an association with other less well-studied diseases is possible.