The goals of this protocol are: 1) to gather and evaluate clinical data on selected patients with FMF and related conditions, so as to characterize more thoroughly the clinical features and natural history of patients with recognized disorders as well as those with as yet undefined autoinflammatory conditions; 2) to identify mutations, both in known autoinflammatory genes and in other genes, that lead to syndromes of periodic inflammation, and to study possible correlations between specific genetic mutations and disease manifestations; and 3) to undertake functional, biochemical, and molecular studies of leukocytes from patients with both known and as yet poorly defined autoinflammatory conditions.