Antisynthetase Syndrome

What is antisynthetase syndrome?

Antisynthetase syndrome is a rare condition that causes inflammation throughout your body. It’s a type of autoimmune disease.

Your immune system is made up of organs and cells meant to protect your body. An autoimmune disease happens when your immune system accidentally attacks your body. It’s unclear why your immune system does this.

Antisynthetase syndrome can affect your:

• Muscles.
• Joints.
• Lungs.
• Skin.
• Blood vessels.

Visit a healthcare provider if you’re noticing new symptoms like joint pain, changes to your skin or trouble breathing.

How rare is antisynthetase syndrome?

Antisynthetase syndrome is rare. Experts aren’t sure exactly how rare it is, but they estimate that fewer than 50,000 people in the U.S. have it.

The exact number is hard to estimate because so few cases are reported each year, and many people may not get diagnosed if their symptoms are treated as other conditions that cause similar symptoms.

What are antisynthetase syndrome symptoms?

Which symptoms you’ll experience depends on where (and how severely) your immune system damages tissue inside your body.

People with antisynthetase syndrome usually have symptoms of a few other conditions, including:

• Myositis: Chronic (long-term) inflammation in your muscles that causes muscle pain and weakness. Myositis can also weaken the muscles in your throat that help you swallow, which causes dysphagia (difficulty swallowing).
• Mechanic’s hands: Thickened, cracked skin on your palms and the sides of your fingers.
• Interstitial lung disease (ILD): ILD damages the tissues between the small air sacs in your lungs (alveoli) and the blood vessels around them. It causes shortness of breath (dyspnea), dry cough, fatigue and chest discomfort.
• Polyarthritis: Polyarthritis is the medical term for having arthritis that affects five or more of your joints at the same time. You’ll feel joint pain, stiffness and swelling in your affected joints.
• Raynaud’s phenomenon (secondary Raynaud’s syndrome): Raynaud’s phenomenon causes color changes and numbness in your fingertips and toes, especially in response to cold.
• Fever: Some people with antisynthetase syndrome develop fevers that aren’t related to or caused by their body fighting off an infection.

What causes antisynthetase syndrome?

Experts aren’t sure what causes antisynthetase syndrome.

Most people with antisynthetase syndrome have specific antibodies in their blood that can show their immune system has been attacking their body instead of protecting it. Providers call these autoantibodies.

Antibodies are proteins that protect you when an unwanted substance enters your body. They’re like chemical signals your immune system uses to flag harmful invaders like bacteria or viruses. If you have an autoimmune disease, your immune system can mistakenly make and send out antibodies that attack healthy tissue.

People with antisynthetase syndrome usually have autoantibodies that attack enzymes called tRNA synthetases. tRNA synthetases are helpful enzymes your body needs to function correctly.

Experts don’t know why your immune system starts making these autoantibodies, but it’s very likely that you have antisynthetase syndrome if there’s evidence of them in your blood.

They’re like the paper scraps and burn marks left on the street after someone’s done setting off firecrackers. You may not know when or why someone was using fireworks outside your house, but you can see the evidence after the fact. And instead of booms and bangs keeping you up at night and scaring your pets, antisynthetase syndrome’s fireworks are the symptoms you experience.

What are the risk factors for antisynthetase syndrome?

Anyone can develop antisynthetase syndrome, but people assigned female at birth (AFAB) and people older than 50 are more likely to have it.

People AFAB are twice as likely to develop antisynthetase syndrome as people assigned male at birth (AMAB).

How is antisynthetase syndrome diagnosed?

A healthcare provider will diagnose antisynthetase syndrome based on your symptoms, a physical exam and some tests.

You might need to visit a rheumatologist, a healthcare provider who specializes in treating autoimmune diseases. They’ll examine your body and ask you about your symptoms. Tell your provider which symptoms you’re experiencing, when you first noticed them and if anything seems to make them worse.

You’ll also need a few tests to help show you have antisynthetase syndrome and to rule out other conditions that cause similar symptoms.

What tests do healthcare providers use to diagnose antisynthetase syndrome?

There’s not one test that can confirm for sure that you have antisynthetase syndrome. Diagnosing it is usually part of a differential diagnosis. This means your provider will probably use a few tests to determine what’s causing your symptoms before ruling out other conditions and diagnosing you with antisynthetase syndrome. Some tests you might need include:

• Blood tests to see how well your immune system is working and to check for the autoantibodies that are a sign of antisynthetase syndrome. Blood tests can also show extra levels of certain enzymes in your blood that mean something is damaging your muscles.
• Urine tests (urinalysis) to check your kidney function and examine your pee for signs of infection or other issues that can cause your symptoms.
• Pulmonary function tests to show if your lungs or respiratory system is affected.
• A computed tomography (CT) scan or other imaging tests to take pictures of tissue and organs inside your body.
• Electromyography (EMG) to check your muscle function.
• Magnetic resonance imaging (MRI) of your affected muscles to check for inflammation.
• A biopsy of your muscle or lung tissue.

How is antisynthetase syndrome treated?

There’s no cure for antisynthetase syndrome, but your healthcare provider will help you find a combination of treatments that manages your symptoms, reduces how much they impact your daily routine and minimizes damage to your organs.

Which treatments you’ll need depends on where you’re experiencing symptoms and how severe they are. Some common treatments include:

• Corticosteroids: Corticosteroids are prescription medications that relieve pain and reduce swelling. Providers often use corticosteroids along with immunosuppressants.
• Immunosuppressants: Immunosuppressants stop your immune system from damaging healthy cells and tissues. Which medication you’ll need depends on which of your organs are affected. Common immunosuppressants include methotrexate, azathioprine and mycophenolate. You may also need cyclophosphamide, rituximab or tacrolimus.
• Treatments to manage interstitial lung disease: You might need medication to improve your breathing, or oxygen therapy if you need extra oxygen. You may work with a lung specialist to manage your breathing.
• Physical therapy: A physical therapist will help you improve how your body physically moves. They can help you manage muscle symptoms or suggest breathing exercises to strengthen your lungs. You might also need pulmonary rehab.

Can I prevent antisynthetase syndrome?

Because experts aren’t sure what causes it or increases your risk, there’s no way to prevent antisynthetase syndrome.

What can I expect if I have antisynthetase syndrome?

Your provider will help you find a combination of treatments that manages your symptoms.

Antisynthetase syndrome is a chronic condition. That means you’ll manage your symptoms for a long time (maybe for the rest of your life).

Is antisynthetase syndrome fatal?

Antisynthetase syndrome usually isn’t fatal. People living with it don’t usually have a different life expectancy than usual. Most people live with it for the rest of their lives but can manage their symptoms with treatments.

It can be fatal if you have severe interstitial lung disease or another complication that affects your respiratory system, but this is rare. Your healthcare provider will tell you what to expect and which changing symptoms can be early signs of severe breathing complications.

When should I see my healthcare provider?

Visit a healthcare provider if you’re experiencing new symptoms, especially if they’re getting worse. Talk to your provider if it feels like your treatments aren’t managing your symptoms as well as they used to, or if your symptoms are starting to make it harder to do all your usual activities.

When should I go to the emergency room?

Go to the emergency room or call 911 (or your local emergency services number) if you have any of the following symptoms:

• Sudden difficulty breathing.
• Severe breathlessness (you feel like you can’t catch your breath).
• Blue skin, lips or nails (cyanosis).
• Chest pain or heaviness.

What questions should I ask my healthcare provider?

• Do I have antisynthetase syndrome or another autoimmune disease?
• Which tests will I need?
• What are the best treatments to manage my symptoms?
• Will I need physical or pulmonary therapy?
• What’s my risk for severe lung complications?

What are other names for antisynthetase syndrome?

Healthcare providers sometimes call antisynthetase syndrome other names, including:

• Antisynthetase deficiency syndrome.
• AS syndrome.
• Anti-Jo1 syndrome.

These are all different names for the same condition.

A note from Cleveland Clinic

Antisynthetase syndrome is a rare condition that happens when your immune system damages your body instead of protecting it. Talk to your provider about the treatments that’ll minimize how much the symptoms affect your day-to-day activities.

Living with an autoimmune disease can be extremely frustrating — it can feel like your body is letting you down or betraying you. Ask your provider about mental health resources if you feel like you need help adjusting to changes in your routine or coping strategies. It’s perfectly healthy to feel upset, but you don’t have to deal with it on your own.