Antisynthetase Syndrome

Antisynthetase syndrome (ASS) is a systemic autoimmune disorder characterized by the triad of inflammatory myopathy (myositis), interstitial lung disease (ILD), and non-erosive arthritis, occurring in the context of autoantibodies directed against aminoacyl-tRNA synthetases. These enzymes catalyze the attachment of specific amino acids to their corresponding transfer RNA (tRNA) molecules, a critical step in protein synthesis. The syndrome represents one of the most clinically significant subsets of idiopathic inflammatory myopathies because of its distinctive clinical features, specific autoantibody associations, and the prominence of interstitial lung disease, which is the leading cause of morbidity and mortality. Aminoacyl-tRNA synthetases (ARSs) are a family of 20 enzymes, each specific to one of the 20 standard amino acids. In antisynthetase syndrome, the immune system generates autoantibodies against one or more of these enzymes. The most common and best-characterized antisynthetase antibody is anti-Jo-1 (anti-histidyl-tRNA synthetase), which accounts for 60-80% of antisynthetase syndrome cases. Other identified antisynthetase antibodies include anti-PL-7 (anti-threonyl-tRNA synthetase), anti-PL-12 (anti-alanyl-tRNA synthetase), anti-EJ (anti-glycyl-tRNA synthetase), anti-OJ (anti-isoleucyl-tRNA synthetase), anti-KS (anti-asparaginyl-tRNA synthetase), anti-Zo (anti-phenylalanyl-tRNA synthetase), and anti-Ha/YRS (anti-tyrosyl-tRNA synthetase). Each antibody is associated with slightly...