Biochemical Clues in unravelling the Puzzle of Anti- synthetase Syndrome.

Anti-synthetase syndrome (ASSD or ASyS) is a rare, systemic autoimmune disorder characterized by the presence of anti-aminoacyl transfer RNA synthetase (anti-ARS) antibodies, most commonly anti-Jo-1. It presents with a combination of myositis, interstitial lung disease (ILD), arthritis, Raynaud's phenomenon, mechanic's hands, and constitutional symptoms, often posing significant diagnostic challenges. We report the case of a 49-year-old male carpenter who presented with persistent cough, progressive dyspnoea, proximal muscle weakness, and joint pain. High-resolution computed tomography (HRCT) of the chest revealed interstitial lung disease with bilateral basal end-inspiratory crepitations noted on physical examination. Serological testing demonstrated anti-Jo-1 antibody positivity, confirming the diagnosis of anti-synthetase syndrome. The patient was initiated on glucocorticoids, hydroxychloroquine, and steroid-sparing immunosuppressive therapy, resulting in symptomatic and functional improvement. This case underscores the importance of early recognition of anti-synthetase syndrome, particularly in patients presenting with unexplained ILD and musculoskeletal symptoms. Delayed diagnosis is often attributed to limited clinical awareness and the restricted availability of routine testing for anti-ARS antibodies, particularly anti-Jo-1, which significantly affects patient outcomes. ILD is a predominant and serious manifestation of ASyS and remains a strong predictor of disease-related morbidity and mortality. Anti-synthetase syndrome should be considered in patients with interstitial lung disease, muscle weakness, and inflammatory arthritis, especially when anti-Jo-1 antibodies are detected. Early diagnosis and immunosuppressive therapy are critical to improving prognosis and preserving lung function.