Gain-of-function point mutations that confer constitutive activation of NLRP3 have been identified as the cause of the three syndromes that comprise the CAPS family: familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS), and neonatal onset multisystem inflammatory disease (NOMID), which have overlapping symptoms of fever, rash and arthralgia but differ in terms of severity, organ manifestations and environmental triggers12–14. The gene discussed is NLRP3; the disease is Muckle-Wells syndrome.