HMGCR and idiopathic inflammatory myopathy: Immune-mediated necrotizing myopathy (IMNM) is a lately identified subtype of idiopathic inflammatory myopathies (IIMs), which are a group of autoimmune diseases usually characterized by auto-antibodies including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) or the signal recognition particle (SRP) (3).