Antisynthetase Syndrome (ASS)

How to pronounce it:

Antisynthetase - ant-eye-sin-theh-tays


AiArthritis defines antisynthetase syndrome as:


Antisynthetase syndrome is a rare, chronic auto-immune disorder that can affect multiple systems of the body. This disorder is often characterized by having autoantibodies (Anti-Jo1) to a specific protein. It is a form of myositis.

Symptoms

Symptoms of AiArthritis Diseases Regardless of Diagnosis

Common in All AiArthritis Diseases



  • Periods of worsening symptoms are called flares. A flare can last for hours, days, weeks, or months.
  • Condition improves with activity and exercise and worsens with rest.
  • When inflammation is left uncontrolled due to lack of proper treatment, comorbidities can develop. 70% of patients with chronic, lifelong disease will develop comorbidities, including dual or triple diagnoses.
  • Autoimmune diseases run in families. If anyone in your immediate family (parents, siblings) or extended family (aunts, uncles, grandparents) have been diagnosed with ANY autoimmune disease, there is the possibility of genetic predisposition.

 “Auto” Symptoms






  • Severe fatigue or exhaustion that may not be helped by caffeine/stimulants and can happen even after a long period of rest.
  • “Brain fog” - or periods of time where thinking gets clouded and it becomes difficult to concentrate.
  • Flu-like symptoms, without having the flu- nausea, muscle weakness, and general malaise.
  • Fever, typically low grade in autoimmune and higher grade in autoinflammatory (% strongly varies per disease).


Reference: Early Symptoms of AiArthritis Study, AiArthritis, 2019.


View Early Symptoms Study

Inflammatory Arthritis Symptoms


  • Severe stiffness in one or more joints, especially in the morning or after sitting for long periods of time. 
  • Episodes of joint pain that may last for hours, days, or even weeks, that can appear and disappear suddenly. Often described as “jumping pain” into different locations.


Typically the joint pain will coincide with one or more “Auto” symptoms and start and stop suddenly - for no apparent reason (which is called a "flare").  Some people will experience all of the above symptoms, others only a few.  If you have any of the arthritis features, and at least one of the “Auto” features, please consult your physician about a referral to a rheumatologist.


Symptoms Often Associated with Antisynthetase Syndrome:

  • Interstitial lung disease (ILD)
  • Raynaud’s Phenomenon - Fingers and toes that turn white or blue when exposed to cold or during stressful periods
  • Mechanic’s Hands (thickened, dry, cracked skin on the sides of the fingers and palms)
  • Loss of appetite
  • Weight loss
  • Polymyositis or dermatomyositis such as muscle weakness, muscle pain, and skin rashes
  • Shortness of breath
  • Coughing
  • Difficulty swallowing (dysphagia)

What fellow patients want you to know

Do you have Antisynthetase Syndrome? Let us know what YOU would want those with Antisynthetase Syndrome or those who are not yet diagnosed to know!

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More About Antisynthetase Syndrome

Diagnosing Antisynthetase Syndrome

There’s no single definitive test that can confirm an antisynthetase syndrome diagnosis, so rheumatologists look at a combination of physical exam (pulmonary function tests, electromyography), blood tests (Anti-tRNA antibody), and imaging (high-resolution computed tomography, MRI), along with a family history of autoimmune or autoinflammatory disease. A biopsy of the muscle, or lung may also be required for a definitive diagnosis.

Interesting Facts about this Disease

  • Females are twice as likely to develop Antisynthetase Syndrome compared to males
  • Up to 75% of those with Antisynthetase Syndrome will develop Interstitial Lung Disease
  • Anti-Jo-1 antibody is most common antisynthetase antibody. Others include PL-7 and PL-12. Five additional antisynthetase antibodies have been identified so far, but there are much more rare


Other Resources

In an effort to ensure this page has the most accurate and up-to-date information, this page is currently awaiting medical review. Some information is subject to change.


Page Last Updated: 9/1/2023

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