Surprisingly, patients with Cryopyrin-associated periodic syndrome (CAPS), which is caused by a gain-of-function mutations in the NLRP3 gene, do develop recurrent fever, uveitis and arthritis, similar to XIAP deficient patients, but do not develop HLH, splenomegaly or IBD (1, 58, 59). The gene discussed is XIAP; the disease is inflammatory bowel disease.