Familial Mediterranean fever is inherited in an autosomal recessive manner. There are two phenotypes: types 1 and 2. Familial Mediterranean fever type 1 is characterized by recurrent short episodes of inflammation and serositis, including fever, peritonitis, synovitis, pleuritis, and, rarely, pericarditis. The symptoms and severity vary among affected individuals, sometimes even among members of the same family. Amyloidosis, which can lead to renal failure, is the most severe complication. Familial Mediterranean fever type 2 is characterized by amyloidosis as the first clinical manifestation of familial Mediterranean fever in an otherwise asymptomatic individual. Routine treatment of end-stage renal disease, including renal transplantation, is advised. Lifelong treatment with colchicine is required for homozygotes for the p.Met694Val mutation or compound heterozygotes for p.Met694Val and another disease-causing allele; this prevents the inflammatory attacks and the deposition of amyloid. Individuals who do not have the p.Met694Val mutation and who are only mildly affected should be either treated with colchicine or monitored every 6 months for the presence of proteinuria. Molecular genetic testing of the MEFV gene, the only gene currently known to be associated with familial Mediterranean fever, can be offered to family members, especially when the p.Met694Val allele is present, because renal amyloidosis can be prevented by colchicine.
- familial Mediterranean fever