What are the other Names for this Condition? (Also known as/Synonyms)

• Anti-OJ Autoantibodies Syndrome
• Anti-PL7 Autoantibodies Syndrome
• AS Syndrome

What is Antisynthetase Syndrome? (Definition/Background Information)

• Antisynthetase Syndrome (or AS Syndrome) is a rare and chronic autoimmune disorder that causes inflammation of the muscles, joints, and lungs. The disorder is more common in female adults
• The cause of AS Syndrome is unknown. It is termed as an autoimmune disorder in which antibodies generated to fight infection, attack the body’s own tissue and destroy aminoacyl-tRNA synthetases, enzymes that are key for protein production
• A healthcare provider typically diagnoses Antisynthetase Syndrome by first testing for the presence of anti-synthetase antibodies in the affected areas, and then performing a variety of related confirmatory tests for other autoantibodies (i.e., antibodies that are directed against one’s own body rather than foreign infectious agents)
• Treatment with prescription strength corticosteroids and other immunosuppressant medications may help relieve some symptoms of Antisynthetase Syndrome in the affected individuals
• The prognosis of Antisynthetase Syndrome is determined by the type of symptomatic presentations of the syndrome and its severity. Those affected only in the muscles often have successful outcomes with long-term treatment

Who gets Antisynthetase Syndrome? (Age and Sex Distribution)

• Although Antisynthetase Syndrome can affect individuals of all ages, it is more common in adults
• Both genders may be affected by the disorder. However, females are more prone than males by a ratio of 2-3:1
• Individuals of all races and ethnicities are known to be susceptible to AS Syndrome

What are the Risk Factors of Antisynthetase Syndrome? (Predisposing Factors)

• The only known risk factor of Antisynthetase Syndrome is belonging to the female gender. AS Syndrome is more than twice as common in women than in men

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Antisynthetase Syndrome? (Etiology)

The cause of Antisynthetase Syndrome is unknown. However, there is some understanding of the underlying biological mechanism related to the condition.

• AS Syndrome is an autoimmune disorder, where antibodies of the body that fight diseases or infections, attack one’s own healthy tissues instead
• Specifically, the condition is characterized by antibodies that attack certain enzymes called aminoacyl-tRNA synthetases. Aminoacyl-tRNA synthetases are enzymes key for protein production
• The specific autoantibodies associated with this condition include:
  • Anti-EJ (glycyl-tRNA synthetase autoantibodies)
  • Anti-OJ (isoleucyl-tRNA synthetase)
  • Anti-PL7 (threonyl-tRNA synthetase)
  • Anti-PL12 (alanyl-tRNA synthetase)
  • Anti-Jo1 (histidyl-tRNA synthetase), which is the most common autoantibody

What are the Signs and Symptoms of Antisynthetase Syndrome?

The signs and symptoms of Antisynthetase Syndrome vary from one individual to another and may include:

• Fever
• Muscle inflammation or myositis
• Multiple joint inflammation (polyarthritis)
• Mechanic’s hands, or the thickening of skin in the finger tips and increased pigmentation along palm creases
• Interstitial lung disease (non-specific lung inflammation), which may present as:
  • Coughing
  • Shortness of breath
  • Chest pain
  • Dysphagia (difficulty swallowing)
  • Acute respiratory failure (in extreme cases)
• Raynaud phenomenon: A condition in which there is reduced blood flow to the extremities in response to low temperatures, causing abnormal whitening of the fingers or toes

How is Antisynthetase Syndrome Diagnosed?

The diagnosis of Antisynthetase Syndrome is made using the following tools:

• A complete physical examination and an assessment of symptoms
• An evaluation of the affected individual’s full medical history
• The identification of autoantibodies directed against aminoacyl-tRNA synthetases (required) through lab tests. These autoantibodies tested may include:
  • Anti-EJ (glycyl-tRNA synthetase) antibodies
  • Anti-OJ (isoleucyl-tRNA synthetase) antibodies
  • Anti-PL7 (threonyl-tRNA synthetase) antibodies
  • Anti-PL12 (alanyl-tRNA synthetase) antibodies
  • Anti-Jo1 (histidyl-tRNA synthetase) antibodies (most commonly associated with AS Syndrome)

Several accompanying clinical tests may lead a healthcare provider to diagnose AS Syndrome. The tests can include:

• Blood tests measuring levels of creatine kinase and aldolase in the muscles (elevated levels are characteristic of AS Syndrome)
• An electromyography (EMG), which measures muscle and muscle nerve health
• Lung functionality tests
• Muscle and lung biopsies
• CT scan of the chest
• MRI scan of the muscles

In some cases, a definitive diagnosis of AS Syndrome may require (along with the presence of AS autoantibodies) 2 major criteria OR, 1 major criterion and 2 minor criteria from the following list:

• Interstitial lung disease (occurring without a known cause) [major]
• Polymyositis (or muscle inflammation) [major]
• Arthritis [minor]
• Raynaud phenomenon [minor]
• Mechanic’s hand [minor]

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Antisynthetase Syndrome?

The potential complications of Antisynthetase Syndrome may include the exacerbation of any variety of symptoms:

• Myositis (muscle inflammation) can lead to muscle decay and weakness, and eventually result in non-functioning tissue
• Interstitial lung disease (lung inflammation) can inhibit breathing when inflammation is severe, which can be fatal

How is Antisynthetase Syndrome Treated?

Treatment of Antisynthetase Syndrome targets the symptoms and treatment measures may include:

• Prescription corticosteroids and other immunosuppressants, which help in reducing inflammation. These medications are often given in high doses initially and slowly decreased over time to reduce the body’s dependence on them
• Physical therapy, which helps in improving the health of affected tissues and offset muscle weakness caused by AS syndrome and related inactivity

How can Antisynthetase Syndrome be Prevented?

Due to the unknown etiology/cause of Antisynthetase Syndrome, there are currently no preventive methods or guidelines available.

• If one develops symptoms of the condition, an early diagnosis followed by prompt treatment may help avoid complications of the syndrome
• Active research is currently being performed to explore the possibilities for treatment and prevention of disorders such as AS Syndrome
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Antisynthetase Syndrome? (Outcomes/Resolutions)

The prognosis of Antisynthetase Syndrome is determined by the type and severity of symptoms in an affected individual.

• Those affected only in the muscles often have success with long-term treatment. Corticosteroid treatment has been found successful in reducing the effects of AS Syndrome, which is indicated by normalized creatine kinase and aldolase levels in subsequent blood tests
• Prognosis of individuals presenting with interstitial lung disease depend on the degree of damage to the lungs. The prognosis is guarded for those with severely affected lungs

Additional and Relevant Useful Information for Antisynthetase Syndrome:

• Antisynthetase Syndrome is classified as an inflammatory myopathy. There are 2 other major conditions also classified as inflammatory myopathies and these include:
  • Dermatomyositis (where there is muscle inflammation and an accompanying skin rash) 
  • Polymyositis (where there is muscle inflammation and no accompanying skin rash)