RAG2 and systemic lupus erythematosus: Other rare genetic defects associated with SLE‐like phenotype affect IKZF1 (encoding for the DNA‐binding protein Ikaros, which is involved in B cell function and regulation96), RAG2 (encoding for the recombination activating gene 2, which is involved in lymphocyte maturation), and phosphatidylinositol‐4,5‐bisphosphate 3‐kinase catalytic subunit delta (PIK3CD); all of which are frequently linked with infections and lymphoproliferation.36, 97