Definition of Familial Mediterranean fever:

Familial Mediterranean fever is a disorder passed down through families (inherited), which involves repeated fevers and inflammation that often affects the abdomen or lungs.

Causes, incidence, and risk factors:

The cause of familial Mediterranean fever is unknown. It usually affects people of Mediterranean ancestry, especially non-Ashkenazi (Sephardic) Jews, Armenians, and Arabs, although people from other ethnic groups may also be affected.

Symptoms usually begin between age 5 and 15. Inflammation in the lining of the abdominal cavity, chest cavity, skin, or joints occurs, along with high fevers that usually peak in 12 to 24 hours. Attacks may vary in severity of symptoms, and people are usually symptom free between attacks.

This disease is very rare. Risk factors include a family history of familial Mediterranean fever or having Mediterranean ancestry.