MEFV and familial Mediterranean fever: Pyrin was first recognized as the initiator of familial Mediterranean fever, the most common monogenic autoinflammatory disease.47, 48 These mutations in familial Mediterranean fever lessen the threshold of activation for the pyrin inflammasome, translating into a hyperinflammatory response.49, 50 Pyrin is unique among PRRs in that it does not fit into any of the known PRR families.