Hereditary periodic fever syndromes

The hereditary periodic fever syndromes are autoinflammatory diseases that mostly present in childhood and are characterized by recurrent, self-limiting, seemingly unprovoked episodes of fever and systemic inflammation that occur in the absence of autoantibody production or identifiable infection.

Disorders include (1) familial Mediterranean fever (FMF), due to mutation in the gene encoding pyrin; (2) tumour necrosis factor (TNF) receptor associated periodic syndrome (TRAPS), due to mutation in a gene for a TNF receptor; (3) Mevalonate kinase deficiency and period fever (MKD), caused by mutations in the mevalonate kinase gene; and (4) the cryopyrin associated periodic syndromes (CAPS), which include (a) familial cold urticarial syndrome, (b) Muckle–Wells syndrome, and (c) chronic infantile neurological, cutaneous and articular syndrome. Understanding of the molecular pathogenesis of these disorders provides unique insights into the regulation of innate immunity and inflammation.

Diagnosis—this relies on recognition of suggestive clinical features (e.g. fever with peritonitis and/or pleurisy, arthralgia/arthritis) that are almost always accompanied by a substantial acute phase response, and is supported by genetic testing. With the exception of FMF, which is prevalent in certain geographic areas, hereditary periodic fever syndromes are rare and easily overlooked in the differential diagnosis of recurrent fevers.

Clinical features and management—attacks can be mild to debilitating and short to prolonged, whilst their most feared complication is AA amyloidosis. Effective therapies are available for some syndromes, e.g. (1) FMF—daily prophylactic colchicine prevents clinical attacks and susceptibility to AA amyloidosis; (2) CAPS—daily treatment with anakinra (recombinant IL-1 receptor antagonist) produces rapid and often complete clinical and serological remission; (3) TRAPS—anti-TNF therapy with etanercept is useful in some patients.