IL1RL2 and familial Mediterranean fever: These are monogenic or polygenic diseases and include familial Mediterranean fever (FMF), TNF receptor-associated periodic syndrome (TRAPS), hyperimmunoglobulinemia D with periodic fever syndrome (HIDS), cryopyrin-associated periodic syndrome (CAPS), Majeed syndrome, Blau’s syndrome, aphthous stomatitis, pharyngitis, and adenitis syndrome (PFAPA), deficiency of interleukin-1 receptor antagonist (DIRA), deficiency of IL-36 receptor antagonist, pyogenic arthritis, pyodermagangrenosum and acne syndrome (PAPA), Crohn’s disease, Still’s disease, and Behçet’s disease.