Immune-mediated necrotizing myopathy is classically associated with anti-signal recognition particle (SRP) and anti-HMG-CoA reductase (HMGCR) antibodies; however, seronegative cases occur and may overlap with DM-specific autoantibodies such as anti-nuclear matrix protein 2 (anti-NXP2). This evidence concerns the gene MORC3 and dermatomyositis.