A rare idiopathic inflammatory myopathy (IIM) characterized by evocative skin lesions, muscle involvement with symmetrical proximal muscle weakness, and specific histological features. The clinical subtypes are defined by the presence of myositis-specific antibodies (anti-Mi2, anti-NXP2, anti-TIF1-γ, anti-MDA5, or anti-SAE antibodies) and are associated with specific clinical phenotypes and prognosis. [from
ORDO]