Autoinflammatory Syndromes

The autoinflammatory syndromes are a group of diseases characterized by apparently spontaneous episodes of fever and inflammatory manifestations in several organs. Some of these conditions, such as familial Mediterranean fever (FMF), have been known for over a century, but others have only recently been defined. The discovery of the genetic defects underlying the pathophysiology of these diseases has been critical for their understanding and eventual grouping in a new category of diseases. Despite their rarity, the monogenic autoinflammatory syndromes are relevant because identification of the causative genetic variants has greatly expanded our understanding of the inflammatory process and the innate immune system and defined new diseases and their treatment. In addition, the autoinflammatory syndromes have been incorporated in the differential diagnosis of fever of unknown origin. In this chapter, the following selected syndromes are reviewed: FMF; cryopyrin-associated periodic syndromes; tumor necrosis factor–associated periodic fever syndrome; hyper-IgD syndrome; pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome; Blau syndrome; deficiency of the interleu