What is the prevalence of familial Mediterranean fever (FMF)?

Updated: May 14, 2018
  • Author: John O Meyerhoff, MD; Chief Editor: Herbert S Diamond, MD  more...
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Answer

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.

In Ashkenazi Jewish people (descended from Eastern European Jewish people and including most European and American Jewish people), the prevalence of FMF is 1 case per 73,000 population, with a MEFV gene frequency now estimated at perhaps 1 per 5, in contrast to previous estimates of 1 per 135. [8] This suggests that not all mutations have equal penetrance.

In Sephardic Jewish people (descended from Jewish people who were expelled from Spain, largely to North Africa, and including other Middle Eastern Jewish populations), the prevalence of FMF is 1 case per 250-1000 population, with a gene frequency of 1 per 8-16.

In Armenian persons (based on epidemiology among Armenian populations in Lebanon and southern California), the estimated prevalence of FMF is 1 case per 500 population, with a gene frequency of 1 per 7.

Turkish people (from one study) may have a prevalence of approximately 1 case per 1000 population. [9]

Arabic people (from one study) may have a prevalence of 1 case per 2600 population in children and a gene frequency of 1 per 50.

Since the development of gene testing, which allows confirmation of FMF in some cases, the disease has been reported in unexpected locations, including by two Japanese groups. [10, 11]

Migrations of guest workers around the world have highlighted the need for physicians to think about formerly uncommon illnesses in their home countries and the need for review articles in national journals. [12]


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