Cryopyrin-associated periodic syndromes and autoinflammation.

Autoinflammatory syndromes are a distinct class of inherited diseases of cytokine dysregulation with important cutaneous features. Several disorders, including familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome and neonatal onset multisystem inflammatory disorder (NOMID), are associated with mutations in a common gene, CIAS-1. These disorders are now believed to represent related conditions along a spectrum of disease severity, in which FCAS is the mildest and NOMID is the most severe phenotype. Patients typically present with lifelong atypical urticaria with systemic symptoms, with potential for developing end-organ damage due to chronic inflammation. Advances in the understanding of the genetic basis of these syndromes have also revealed cytokine signalling molecules that are critical to normal regulation of inflammatory pathways. The dramatic response of these syndromes to anakinra, an interleukin (IL)-1 antagonist, highlights the important role of IL-1 cytokine signalling in the pathogenesis of this rare but fascinating class of diseases.