Definition:

Familial Mediterranean fever (FMF) is the most prevalent hereditary periodic fever, affecting 0.1% in people of Mediterranean descent. It is also reported throughout the world's populations. FMF is an autosomal recessive disorder caused by missense mutations in the MEFV gene, which encodes the pyrin protein. Mutations in pyrin may lead to uncontrolled inflammation due to IL-1beta hyperactivation. FMF is characterized by recurrent inflammatory fevers with sterile peritonitis, pleuritis, arthritis, myalgia and erysipelas-like skin lesions. Renal amyloidosis is the most severe complication, leads to renal failure. These symptoms start before 20 years of age in about 90% of cases.