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Diseases

Genetic and Rare Diseases Information Center (GARD)

Familial Mediterranean fever


Other Names for this Disease
  • Periodic peritonitis
  • Recurrent polyserositis
  • Benign paroxysmal peritonitis
  • Periodic disease
  • Familial paroxysmal polyserositis
Related Diseases
  • Secondary glomerular disease
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Inheritance

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How is familial Mediterranean fever (FMF) inherited?

FMF is almost always inherited in an autosomal recessive manner.[1] This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not show signs or symptoms of the condition. When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier. As many as 1 in 5 people of Sephardic (non-Ashkenazi) Jewish, Armenian, Arab and Turkish heritage are carriers for FMF.[2] 

In rare cases, this condition appears to be inherited in an autosomal dominant manner.[1] This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family. A person with FMF inherited in an autosomal dominant manner has a 50% chance with each pregnancy of passing along the altered gene to his or her child.

In some cases, FMF may appear to be autosomal dominant when it is actually autosomal recessive. This phenomenon is called pseudodominance. This may happen in families if one parent is an unaffected, unknown carrier (with 1 mutation) and the other parent is affected (with 2 mutations). It may appear that an affected child inherited FMF from only the affected parent, when in fact he/she inherited one mutation from each parent.[1]
Last updated: 12/8/2015

References
  1. Familial Mediterranean Fever. Genetics Home Reference (GHR). June 2014; http://ghr.nlm.nih.gov/condition=familialmediterraneanfever. Accessed 12/8/2015.
  2. Learning about Familial Mediterranean Fever. NHGRI. November 2011; http://www.genome.gov/12510679. Accessed 12/8/2015.


Other Names for this Disease
  • Periodic peritonitis
  • Recurrent polyserositis
  • Benign paroxysmal peritonitis
  • Periodic disease
  • Familial paroxysmal polyserositis
Related Diseases
  • Secondary glomerular disease
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.