Almost exclusively found in IIM patients, MSAs include antisynthetase autoantibodies (ARS), anti-Mi-2, anti-signal recognition particle (SRP), anti-melanoma differentiation-associated gene 5 (MDA5), anti-nuclear matrix protein 2 (NXP2), anti-transcription intermediary factor 1γ (TIF1γ), anti-small ubiquitin-like modifier activating enzyme (SAE), and anti- 3-Hydroxy-3-methylglutaryl CoA reductase (HMGCR). This evidence concerns the gene MORC3 and acquired idiopathic inflammatory myopathy.