IL21 and psoriatic arthritis: The KIAA1109-TENR-IL2-IL21 region has been associated with a number of autoimmune phenotypes including type 1 diabetes (T1D) [13], ulcerative colitis [14], Crohn's disease [15], celiac disease [16], Graves' disease (GD) [13], systemic lupus erythematosus (SLE) [17], psoriatic arthritis [18], and juvenile idiopathic arthritis [19] (Table 1).