MEFV and cryopyrin-associated periodic syndrome: The wide heterogeneity of the CAPS phenotype is partly explained by the many different mutations of the inflammasome NLRP3 gene which have been described in CAPS patients.100 Another inflammasome protein, pyrin, is encoded by the MEditerranean FeVer (MEFV) gene, mutations in which cause Familial Mediterranean Fever (FMF).