Familial Mediterranean fever (FMF) is also called recurrent. The salient features of FMF include brief recurrent episodes of peritonitis, pleuritis, and arthritis, usually with accompanying fever. As the name indicates, FMF occurs within families and is much more common in individuals of Mediterranean descent than in persons of any other ethnicity.
Symptoms of familial Mediterranean fever include fever, abdominal pain, chest pain, achy, swollen joints, constipation followed by diarrhea etc.
Nonsense or missense mutations in the MEFV (Mediterranean fever) gene appear to cause the disease in many cases. MEFV produces a protein called pyrin (derived from the association with predominant fever) or marenostrin (derived from the phrase "our sea," because of the Mediterranean heritage of most patients).
The frequency of FMF in any location depends on the ethnic background of the population. To survive ethnic and religious persecution, many Mediterranean families converted to other religions or intermarried members of other ethnic groups, thus carrying the MEFV gene with them.