Antisynthetase syndrome is a chronic autoimmune disease that affects the muscles and other parts of the body. Signs and symptoms can vary but may include muscle inflammation (myositis), polyarthritis (inflammation of many joints), interstitial lung disease, thickening and cracking of the hands, and Raynaud phenomenon. Although the underlying cause of antisynthetase syndrome is unknown,, the production of autoantibodies (antibodies that attack normal cells) that attack certain enzymes in the body called ‘aminoacyl-tRNAsynthetases’ appears to be linked to the cause of the syndrome. These autoantibodies may arise after viral infections, or patients may have a genetic predisposition. Treatment is based on the signs and symptoms present in each person but may include corticosteroids, immunosuppressive medications, and/or physical therapy.