C4A and systemic lupus erythematosus: Several SLE associated INDELs and SVs have previously been reported in SLE, which are exemplified by a 5 bp INDEL close to IRF5 [26], copy number variation of FCGR3A and FCGR3B [27] in synergy with copy number variation of ADAM3A [28], and copy number variation of C4 [29], as well as population specific CNVs in TLR7, DEFB4, RABGAP1L, and HLA-DRB5 [28].