Familial Mediterranean fever (FMF) is an autoinflammatory disorder that involves recurring episodes of fever and inflammation of the serous tissues, which line a person’s organs.

FMF typically affects people of Mediterranean origin. Other names that healthcare professionals may use for this condition include Reimann syndrome, periodic fever disease, and Siegel-Cattan-Mamou disease.

During active episodes, people with FMF may experience severe pain across the body and may have symptoms such as a headache or rash.

FMF episodes tend to get better by themselves. Healthcare professionals can also prescribe treatments to prevent these episodes and reduce the risk of complications.

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The MEFV gene is responsible for FMF. In most cases, mutations affecting this gene cause FMF. However, around 10% of people with FMF do not have any associated MEFV gene mutation.

The MEFV gene encodes a protein called pyrin, which helps to regulate inflammation.

FMF is an autosomal recessive condition. Autosomal means the condition does not affect a chromosome related to a person’s sex. Recessive means people require two copies of the gene to inherit the condition.

Therefore, people only inherit FMF if they receive the necessary gene mutation from both parents.

If someone only receives one copy of the gene mutation that causes FMF, they may be a carrier of the disease but will not necessarily have symptoms.

Episode triggers

FMF involves recurring episodes of symptoms. According to a 2024 article, theories about the triggers for these episodes vary, and specific triggers may vary from person to person depending on the type of gene mutation they have.

However, some potentially common triggers include:

  • stress
  • cold exposure
  • humidity
  • seasonal changes
  • relocation or traveling for long durations

FMF typically affects people of Mediterranean or Middle Eastern descent. However, a 2019 review suggests it is becoming more common outside the Mediterranean basin.

A 2023 review suggests that FMF may be most common in Turkey, affecting 1 in 1,000 people. However, FMF rates vary by region even in a single country.

The review suggests that FMF prevalence is increasing in parts of the world, such as the United States and North African countries. Some people in Japan also appear to have a milder form of FMF, which starts later in life and involves fewer complications.

FMF involves recurring bouts of symptoms, called episodes. These episodes typically first begin in childhood. They may develop over a few hours and last up to four days.

According to the National Organization for Rare Disorders, FMF symptoms vary significantly from person to person. However, potential symptoms include the following:

Some people may experience changes in mood, such as irritability or anxiety, before an episode starts.

FMF episodes are not necessarily predictable. They may occur anywhere from once a week to every few months or longer.

Prompt diagnosis is important to speed up treatment, which can reduce FMF episodes and the risk of complications.

To diagnose FMF, a doctor will ask about a person’s symptoms and look at their family medical history. For a diagnosis, people must typically experience at least three episodes of high fever and pain due to inflammation, lasting up to 72 hours.

Laboratory and genetic tests can help to confirm their diagnosis. They may also prescribe colchicine to see if a person’s symptoms improve, which can confirm their diagnosis.

The main goal of FMF treatment is to reduce the frequency of episodes and prevent complications. Typically, a healthcare professional will prescribe colchicine (Colcrys), a medication that helps to reduce inflammation.

People usually need to take colchicine for the rest of their lives to manage FMF. The necessary dose can depend on a person’s age, symptoms, and whether they experience side effects.

The most common side effects are vomiting and diarrhea. If these occur, a healthcare professional may suggest splitting the daily dose into two or three doses. However, people should not alter their dosage without speaking with their healthcare team first.

If colchicine does not relieve episodes or a person does not respond well to this drug, doctors may prescribe IL-1 inhibitors, such as canakinumab (Ilaris) or anakinra (Kineret).

People can also work to reduce the risk of episodes by learning and avoiding their triggers.

Research is ongoing to investigate other potential medications and treatments for FMF.

The main complication of FMF is AA amyloidosis. Amyloidosis refers to a group of conditions that occur when the protein amyloid builds up in the body. It affects a person’s organs. Symptoms may depend on the affected body part.

Amyloidosis can cause health issues such as kidney failure, infertility, and inflammatory disorders, such as ankylosing spondylitis and Behçet’s disease.

There is no cure for amyloidosis, and people typically require lifelong treatment to manage the condition.

Other rare complications include:

  • glomerulonephritis, the inflammation and scarring of part of the kidneys
  • IgA vasculitis, an autoimmune disease that affects small blood vessels
  • polyarteritis nodosa, which causes damage and inflammation to small arteries

Treatment for FMF can prevent these complications. However, treatment is typically lifelong.

Since FMF typically first appears in childhood, parents or caregivers can aid a diagnosis by speaking with a healthcare professional if their child experiences recurring episodes of fever and inflammation.

People with FMF can manage their episodes and reduce the risk of complications with treatment. However, if their current treatment does not relieve their symptoms or they experience side effects, they should speak with their doctor.

Their healthcare team may choose to adjust their dosage or try a new treatment type to help them manage their condition.

FMF can cause severe symptoms for some people, which may affect their mental health. A healthcare professional can help with any associated mental health challenges that may occur after a FMF diagnosis.

There is no cure for FMF. However, treatments can help a person prevent episodes and complications.

To inherit FMF, a person must receive copies of the necessary gene mutations from both parents. People with FMF can have children, though they may benefit from working with a healthcare professional to reduce the risk of passing this condition to their child.

Around 90% of first FMF episodes occur before a person turns 20. However, in rare cases, a person may experience their first episodes and diagnosis later in life.

Familial Mediterranean fever (FMF) is a condition that involves recurring episodes of fever and inflammation. It typically affects people of Mediterranean and Middle Eastern descent, but is growing in prevalence in other parts of the world.

Symptoms of FMF vary from person to person. Even two people with FMF in the same family may present very differently. Triggers of episodes may include stress and certain extreme temperatures.

Treatment of FMF usually involves lifelong daily colchicine. This can prevent the occurrence of FMF episodes and complications, such as amyloidosis.