What Is Familial Mediterranean Fever (FMF)?
Familial Mediterranean fever (FMF) is a rare genetic disease that runs in families. Most often, it affects people whose ancestors came from countries around the Mediterranean Sea and the Middle East. This includes ethnic groups like Arabs, Armenians, Sephardic or North African Jews, Turks, Greeks, and Italians.
FMF is an autoinflammatory syndrome. That means you have recurring episodes of inflammation and fevers related to a defect in your innate immune system. It’s the most common autoinflammatory syndrome. It’s also called hereditary periodic fever syndrome.
Nearly all people with FMF start having periodic fevers before age 20. Three-quarters of people with this condition have their first episodes before age 10. All genders can get it.
FMF is caused by a mutation in a gene called MEFV. Children who have it usually inherit copies of the faulty MEFV gene from both parents. Some can develop symptoms that are very similar to FMF even if they inherit only one copy of the faulty gene from one parent. There are more than 300 different MEFV mutations, but only a few cause FMF.
MEVF is a gene that makes a protein called pyrin. Pyrin seems to play a role in how your body’s immune system functions. If you have an MEFV gene mutation, your body doesn’t make enough pyrin. As a result, your immune system may make too much of an inflammatory cytokine called interleukin-1B. That causes recurring bouts of inflammation and fevers.
FMF often causes fever attacks that may last for up to 3 days. Fevers can spike up to 104 degrees. Along with a fever, it can cause joint pain and swelling, typically in the knee or ankle. A child’s joint may be so painful and swollen that they can’t walk.
These joint pain attacks may be misdiagnosed at first as juvenile idiopathic arthritis (JIA). Their joint may stay swollen for a week or two, then get better. Some children have long-term joint symptoms.
FMF may cause these symptoms too:
- Red skin rash on the calves, ankles, or feet
- Severe abdominal pain
- Chest pain
- Achy muscles
- Constipation followed by diarrhea
FMF flares may be triggered by an infection, stress, strenuous exercise, physical trauma, or even getting your period. Between flares, people with FMF often feel normal. They may be symptom-free for years between flares.
It’s rare, but some children with FMF can develop these serious complications:
- Myositis, or muscle inflammation
- Pericarditis, an inflammation of tissue around the outside of the heart
- Meningitis, an inflammation of tissue around the brain or spinal cord
- Inflammation of the testicles
- Enlarged spleen
- Amyloidosis, a protein buildup in the urine that may cause serious kidney damage
People with FMF have a higher risk of developing some other inflammatory diseases:
- Vasculitis, or blood vessel inflammation, such as Behçet’s disease
- Ulcerative colitis (UC)
- Crohn’s disease
- Rheumatoid arthritis (RA)
People with untreated FMF may become infertile, especially if they also have severe flares or develop amyloidosis.
Getting a Diagnosis
Your doctor will perform these tests to diagnose FMF:
Physical exam. They’ll go over you or your child’s symptoms and rule out any other possible causes.
Family history. Because this disease is inherited, your doctor will ask if you or anyone in your family have been diagnosed with or had symptoms that suggest it.
Blood tests. Your child’s blood may show signs of high inflammation, such as high levels of some white blood cells, high erythrocyte sedimentation rate (ESR), or high C-reactive protein (CRP).
Urinalysis. High amounts of protein or small amounts of blood in the urine is a sign of kidney problems related to FMF attacks.
Genetic test. A DNA test can show if your child has one or two copies of an MEFV gene mutation. But there are hundreds of possible mutations to MEFV, so it’s possible that a genetic test could be false-negative.
Don’t delay diagnosis. Be sure to get a prompt, confirmed diagnosis of FMF. Children with severe abdominal pains may be misdiagnosed with appendicitis and have unnecessary surgery.
Questions for Your Doctor
You’ll probably have a lot of questions for your doctor or your child’s pediatrician. Here are a few questions you might wish to ask:
- What are the possible causes for these symptoms other than FMF?
- What causes FMF?
- Why does FMF run in some families?
- What are the treatments available for my child?
- What are the possible side effects of FMF treatments that my child may experience?
- If my child has any complications of FMF like other inflammatory diseases, how will they be treated?
- Should I restrict my child’s activities, or can they continue to play sports or exercise?
- What’s the risk of FMF for my other children? Should all my children get genetic testing?
- If my partner and I wish to have more children, will they develop FMF?
- How can I lower the risk of infertility in my children diagnosed with FMF?
There’s no cure for FMF, but treatments can prevent and relieve symptoms.
Colchicine is a generic medicine that controls inflammation in FMF. It’s taken as a pill once or twice a day. Colchicine can prevent FMF flares, but if you or your child is already having an episode, the drug won’t treat it. Colchicine needs to be taken regularly to work. Flares can return if you miss even one dose. Children who take colchicine regularly can have a full, normal life with FMF.
Colchicine’s most common side effects are abdominal pain and diarrhea. Your doctor can reduce your child’s dose for a little while if side effects occur. Milk and other dairy products may trigger these side effects, so cut back on milk or switch to lactose-free dairy products. Colchicine may also cause nausea, vomiting, or belly cramps.
- Rarely, colchicine can cause muscle weakness, especially if taken with statins or the antibiotic drug erythromycin.
- Children on colchicine will need blood and urine tests twice a year.
- Colchicine is safe to use while pregnant or breastfeeding.
If colchicine doesn’t work or your child can’t tolerate it, drugs that block interleukin-1, a protein linked to inflammation in FMF, may help. These drugs include anakinra (Kineret), canakinumab (Ilaris), and rilonacept (Arcalyst).
NSAIDs and analgesics. Nonsteroidal anti-inflammatory drugs (NSAIDs) and pain medications, or analgesics, may help relieve fevers or joint pain during a flare.
Taking Care of Your Child
Your child may need emotional support or counseling when they’re diagnosed and learn that they have to take medicine every day for life. If your child’s fevers keep them out of school or social activities, it may be upsetting.
Tell your child’s school principal, teachers, and counselors that your child has been diagnosed with FMF so they can be aware of symptoms and help them keep up with schoolwork if they have to stay home for a few days.
What to Expect
Having FMF means you must take your medication for life to prevent flares and control inflammation. Make sure you or your child takes the medication on schedule. With treatment, you can have a normal, full life with FMF.
FMF can raise the risk of amyloidosis. Daily colchicine prevents amyloidosis, and if caught early, amyloidosis is treatable. If it gets worse, amyloidosis can require kidney dialysis or transplant. You’ll need urine tests twice a year to look for signs of high amyloid proteins.
Living with FMF or any lifelong disease can be stressful. You may be upset that you’ve passed a gene mutation to your children. Here are some tips to help you or your child cope:
- Check out online support groups for people with autoinflammatory diseases like FMF, such as rareconnect.org.
- Learn more about FMF. Ask your doctor questions about your child’s diagnosis and to suggest resources to help you and your family manage any stress you feel.
- Reach out for help when you need it. Ask family members or friends to help you with tasks when you’re caring for your child during fever episodes. Find someone you trust to talk to when you just need to vent.