Specifically, the presence of systemic inflammation, amyopathic myositis (characterized by normal CK and LDH levels), interstitial pulmonary fibrosis with mildly reduced DLCO confirmed by HRCT, and a distinct serologic profile—positive anti-Ro/SSA, anti-Ro 52, and anti-Pl 12 antibodies—established the diagnosis of anti-PL-12-positive ASyS presenting with ILD and arthritis, in the absence of overt myositis. This evidence concerns the gene TRIM21 and myositis disease.