Familial Mediterranean Fever (MEFV)
Familial Mediterranean fever is an autosomal recessive disorder caused by pathogenic variants in the gene MEFV. It is particularly common in Middle Eastern and Mediterranean populations, as well as individuals of Ashkenazi or Sephardic Jewish ancestry. Clinical symptoms are variable, with some patients having mild forms and never requiring clinical attention. Two main forms of the disease exist: Type 1: Recurrent bouts of fever, inflammation and pain in the abdomen or the joints. Depending on the individual, these bouts may occur often or rarely. Each episode typically lasts about 3 days. Some patients have symptoms of discomfort before an episode begins. Type 2: Some patients who do not experience fever episodes may develop a buildup of proteins called amyloids in the kidneys. This can lead to kidney damage and end-stage renal disease, requiring dialysis or kidney transplant. Life expectancy is not reduced, except in untreated patients with severe kidney manifestations. Certain variants are associated with more severe disease, development of amyloidosis, and earlier onset of symptoms.
For information about carrier frequency and residual risk, please see the residual risk table.