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Familial Mediterranean fever is an inherited auto-inflammatory condition that causes repeated episodes of:

  • high fevers
  • stomach pain
  • chest pain
  • joint pain

The condition generally first appears during childhood and is most common in people of Mediterranean and Middle Eastern descent.

There’s no cure for familial Mediterranean fever, but medication can manage the condition. If left untreated, familial Mediterranean fever can lead to organ damage and kidney failure.

This article takes a deeper look at this condition, including symptoms, causes, diagnosis, and treatment.

Familial Mediterranean Fever (FMF) is a rare genetic condition that’s most common in people of Mediterranean and Middle Eastern descent. FMF causes episodes of high fever and other symptoms that last for a few days at a time.

People generally feel healthy between episodes. The time between episodes can range from days to years.

About 80 to 90 percent of people with FMF have their first episode before they reach age 20. An estimated 75 percent of people with FMF have their first episode before they reach age 10.

The primary symptom of FMF is a fever. For some people, a fever might be the only symptom. This is especially common in children. Symptoms can change over time and might vary from episode to episode.

Symptoms beyond a fever can include:

  • Abdominal pain and swelling. Abdominal pain can be mild or so severe it’s mistaken for appendicitis.
  • Chest pain. Chest pain ranges from mild to severe enough to make breathing difficult.
  • Joint pain and swelling. Joint pain might be general aches or deep pain that makes it hard to walk.
  • Rash. Rash generally covers the ankles and feet.
  • Muscle pain. Muscle pain is most common in the legs but is sometimes felt through the body.
  • Tissue inflammation. The tissues that line the heart, lungs, and stomach can become inflamed during an episode.

Generally, symptoms will appear during the first 1 to 3 days of a typical FMF episode and then resolve. In some cases, joint pain and muscle pain can last weeks or longer. Some people with FMF have joint pain in a specific joint that comes and goes, even when they’re not having an FMF episode.

FMF is an inherited disorder caused by a mutation on the MEFV gene. The MEFV gene is responsible for making a protein called pyrin that controls inflammation. When this gene doesn’t work correctly, it can cause the body to have fever and pain even when no infection is present in the body.

FMF is generally considered recessive, meaning you need to receive a copy of the mutated MEFV gene from each biological parent to develop FMF. However, FMF is sometimes found in people who only have one MEFV.

Risk factors for familial Mediterranean fever

There are a few risk factors for FMF. Risk factors are tied to the way the MEFV gene is inherited and include:

  • Having Mediterranean or Middle Eastern ancestry. FMF is rare in many populations but occurs in about 1 in 200 people of Sephardic Jewish, Armenian, Arab, and Turkish ancestry. FMF is also commonly found in people with North African, Greek, Italian, Ashkenazi Jewish, Spanish, and Cypriot ancestry.
  • Having a family history of FMF. Your risk of FMF is increased if anyone in your family has been diagnosed with FMF.

FMF is often suspected in children who have unexplained episodic fevers and who have ancestry associated with FMF. Doctors generally look for the following factors in making an FMF diagnosis:

  • episodic fevers and other FMF symptoms
  • Mediterranean or Middle Eastern ancestry
  • lab results that indicate an immune system response, such as high white blood cell count or erythrocyte sedimentation rate (ESR)
  • genetic testing that indicates the presence of a mutated MEFV gene

Genetic testing on its own is not enough to diagnose FMF. Sometimes, a diagnosis of FMF can be difficult to confirm.

A doctor might prescribe trial use of the medication colchicine for a few months to see if episodes stop. A lack of episodes while taking colchicine can confirm an FMF diagnosis because colchicine is the primary treatment for FMF.

There’s no cure for FMF. However, it can be controlled with daily, life-long use of the anti-inflammatory medication colchicine. The medication is taken once or twice per day and prevents episodes in most people with FMF.

Colchicine doesn’t treat an episode that has already started, and missing even one dose can trigger an episode.

Regular use of colchicine can help people with FMF manage their condition and can prevent serious complications.

FMF can be controlled with the use of colchicine. However, without treatment, it can lead to serious complications. These include:

  • Organ damage. FMF can cause an abnormal protein called amyloid A to build up in your blood during episodes. The protein buildup can cause organ damage, also known as amyloidosis.
  • Kidney failure. Damage to your kidney’s filtering system can lead to blood clots and kidney failure.
  • Arthritis. The joint pain of FMF can lead to progressive joint damage and arthritis.
  • Infertility in people assigned female at birth. Organ damage can include female reproductive organs and lead to infertility.

Rarely, organ damage is the first sign of FMF. This is often referred to as FMF type 2. People with FMF type 2 will have no other symptoms.

Familial Mediterranean fever is an inherited chronic condition that causes episodes of high fever and other symptoms. Episodes generally last for 1 to 3 days, and people are often symptom-free between episodes.

The time between episodes can range from days to years. Most people have their first episode during childhood.

There is no cure for FMF, but the condition can be managed by taking colchicine to prevent episodes and complications.