Familial Mediterranean fever is an inherited disorder that usually occurs in people of Mediterranean origin — including those of North African, Jewish, Arab, Armenian, Turkish, Greek or Italian ancestry. But it can affect people in any ethnic group.

Familial Mediterranean fever is typically diagnosed during childhood. While there's no cure for this disorder, you may be able to relieve signs and symptoms of familial Mediterranean fever — or even prevent them altogether — by sticking to your treatment plan.

Symptoms

Signs and symptoms of familial Mediterranean fever usually begin during childhood. They occur in bouts called attacks that last one to three days. Arthritic attacks may last for weeks or months.

Signs and symptoms of familial Mediterranean fever include:

• Fever
• Abdominal pain
• Chest pain
• Achy, swollen joints
• A red rash on your legs, especially below your knees
• Muscle aches
• A swollen, tender scrotum

Between attacks, you'll likely feel normal. Symptom-free periods may be as short as a few days or as long as several years.

Causes

Familial Mediterranean fever is caused by a gene mutation that's passed from parents to children. The gene mutation causes problems in regulating inflammation in the body.

In people with familial Mediterranean fever, the mutation occurs in a gene called MEFV. Many different mutations in MEFV are linked to familial Mediterranean fever. Some mutations may cause very severe cases, while others may result in milder signs and symptoms.

Risk factors

Factors that may increase the risk of familial Mediterranean fever include:

• Having a family history of the disease. If you have a family history of familial Mediterranean fever, your risk of the disease is increased.
• Being of Mediterranean ancestry. If your family can trace its history to the Mediterranean region, your risk of the disease may be increased. Familial Mediterranean fever can affect people in any ethnic group, but it may be more likely in people of North African, Jewish, Arab, Armenian, Turkish, Greek or Italian descent.

Complications

Complications can occur if familial Mediterranean fever isn't treated. Complications can include:

• Abnormal protein in the blood. During attacks of familial Mediterranean fever, your body may produce an abnormal protein (amyloid A). The protein can accumulate in your body and cause organ damage (amyloidosis).
• Kidney damage. Amyloidosis can damage the kidneys, causing nephrotic syndrome. Nephrotic syndrome occurs when your kidneys' filtering systems (glomeruli) are damaged. People with this condition may lose large amounts of protein in their urine. Nephrotic syndrome can lead to blood clots in your kidneys (renal vein thrombosis) or kidney failure.
• Infertility in women. Inflammation caused by familial Mediterranean fever may also affect the female reproductive organs, causing infertility.
• Joint pain. Arthritis is common in people with familial Mediterranean fever. The most commonly affected joints are the knees, ankles, hips and elbows.

Diagnosis

Tests and procedures used to diagnose familial Mediterranean fever include:

• Physical exam. Your doctor may ask you about your signs and symptoms and conduct a physical exam to gather more information.
• Review of your family medical history. A family history of familial Mediterranean fever increases your likelihood of developing the condition because this genetic mutation is passed from parents to their children.
• Blood tests. During an attack, blood tests may show elevated levels of certain markers that indicate an inflammatory condition in your body. An elevated level of white blood cells, which fight infections, is one such marker.
• Genetic testing. Genetic testing may determine if your MEFV gene contains a mutation that is associated with familial Mediterranean fever. Genetic tests aren't advanced enough to test for every gene mutation that's linked to familial Mediterranean fever, so there is a possibility of false-negative results. For this reason, doctors typically don't use genetic tests as the sole method of diagnosing familial Mediterranean fever.

Treatment

There's no cure for familial Mediterranean fever. However, treatment can help prevent signs and symptoms.

Medications used to control signs and symptoms of familial Mediterranean fever include:

• Colchicine. This drug, taken in pill form, reduces inflammation in your body and helps prevent attacks. Work with your doctor to determine the best dosing strategy for you. Some people take one dose a day, while others need smaller, more-frequent doses. Common side effects include bloating, abdominal cramps and diarrhea.
• Other drugs to prevent inflammation. For people whose signs and symptoms aren't controlled with colchicine, medications that block a protein called interleukin-1, which is involved in inflammation, may be prescribed. These medications include canakinumab (Ilaris), rilonacept (Arcalyst) and anakinra (Kineret).