In addition to antibody variation, polymorphisms at CLEC16A and CIITA have been associated with numerous autoimmune diseases, including multiple sclerosis [79,80], diabetes [81], Crohn’s disease [82], adrenal insufficiency [83] and arthritis [84], and CLEC16A has been functionally linked to auto-inflammation and autoimmunity in mice [85]. Here, CIITA is linked to Crohn disease.