NLRP3 and cryopyrin-associated periodic syndrome: 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).