What is Antisynthetase Syndrome?

Simply Put

By definition, the term “syndrome” means a group of signs and symptoms which consistently occur together. It is also referred to as a “constellation” of symptoms.

Antisynthetase Syndrome (ASS) is one such constellation and is included in the acquired inflammatory myopathy category because approximately 90% of people with Antisynthetase Syndrome experience Myositis.

Signs & Symptoms of ASS

  • Polymyositis or Dermatomyositis (primary muscle weakness in the thighs, shoulders, upper arms, and neck)
  • Interstitial Lung Disease (see ILD)
  • Raynaud’s Phenomenon
  • Inflammatory Polyarthritis
  • Mechanic’s hands
  • Fever

Quick Tips

Antisynthetase syndrome is a rare medical syndrome associated with interstitial lung disease, Dermatomyositis, and Polymyositis, and other autoimmune diseases.

ASS is a very rare disease within a very rare disease, so physicians’ lack of experience can result in an inaccurate diagnosis.

An accurate and expeditious diagnosis is vital for proper treatment, especially when there is lung involvement.

Anti-Jo-1 is the predominant autoantibody seen in Antisynthetase Syndrome and is present in an estimated 70-90% of patients with Myositis who have associated Interstitial Lung Disease.

Diagnosing and Treating Antisynthetase Syndrome

Correct diagnosis can be challenging for a variety of reasons. Not all symptoms are necessarily present or apparent, especially early in the disease process, and some symptoms may be so mild that the patient and/or physician fails to notice or relate them to the other symptoms. Additionally, it is a very rare disease within a very rare disease, so physicians’ lack of experience can result in an inaccurate diagnosis.

An accurate diagnosis is vital for proper treatment, especially for lung involvement. The lung disease may be misdiagnosed as Idiopathic Pulmonary Fibrosis, a progressive lung disease which does not typically respond to immunosuppressive drug treatment, and lung transplantation is the only recommended option offered. However, Interstitial Lung Disease associated with Anti-Synthetase Syndrome often responds to immunosuppressive drug therapy as do the other symptoms which accompany Antisynthetase Syndrome.

Rituxan (Rituximab) has also been found to be an effective treatment of Antisynthetase Syndrome, as has IVIG which appears to be especially helpful in alleviating the esophageal symptoms.

Autoantibodies

Anytime Myositis is suspected, it is advisable for the physician to run a Myositis-Specific Panel, a blood test which determines if certain autoantibodies exist which are primarily or solely associated with Myositis. Testing positive to any of the Myositis-specific antibodies can determine the likely progression of the disease, possible other diseases which may be associated with the particular autoantibody, such as Antisynthetase Syndrome or cancer, and may be able to suggest a more effective treatment regimen.

Anti-Jo-1 is the predominant autoantibody seen in Antisynthetase Syndrome and is present in an estimated 70-90% of patients with Myositis who have associated Interstitial Lung Disease.   Seven other autoantibodies are also seen with Antisynthetase Syndrome, however, these autoantibodies constitute only about 3% of Myositis/Interstitial Lung Disease patients.

antisynthetase antibodies

Cancer and Antisynthetase Syndrome

While it was once believed that cancer was not associated with Antisynthetase Syndrome, recent studies indicate an association, especially cancers occurring within 6 to 12 months of onset of symptoms.   It is recommended that age-appropriate cancer screenings be conducted upon diagnosis. (See Myositis-Cancer Connection)

Simply Put

“Simply Put” is a service of Myositis Support and Understanding, to provide overviews of Myositis-related medical and scientific information in understandable language.

MSU volunteers, who have no medical background, read and analyze often-complicated medical information and present it in more simplified terms so that readers have a starting point for further investigation and consultation with healthcare providers. The information provided is not meant to be medical advice of any type.

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Hi, this may be interesting to you: Antisynthetase Syndrome (ASS)! The link is included below: https://understandingmyositis.org/myositis/antisynthetase-syndrome/ --- Myositis Support and Understanding is a 501(c)3 nonprofit organization.