Cryopyrin-associated periodic syndromes (CAPS) comprise a group of rare auto-inflammatory diseases, which include the Familial Cold Auto-inflammatory Syndrome (FCAS), the Muckle-Wells Syndrome (MWS), and the Neonatal-Onset Multiorgan Inflammatory Disease (NOMID) and are caused by mutations in the NLRP3 (CIAS1/NALP3/PYPAF1) gene, encoding for cryopyrin/NALP3 protein. This evidence concerns the gene NLRP3 and Muckle-Wells syndrome.