ABSTRACT
Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) myopathy is one of the subtypes of immune-mediated necrotizing myopathy. Anti-HMGCR antibodies induce complement activation,subsequently resulting in myofiber necrosis,regeneration with autophagy abnormalities and mitochondrial changes. The age of onset is from children to adulthood. Some patients have a history of exposure to statins. Most patients are subacute onset. The patients with chronic progressive process, are more like muscular dystrophy. The main symptoms are proximal symmetrical weakness of limbs and usually accompanied with extra-muscle symptoms. The MRI showed muscle edema in all patients and fatty infiltrates in some patients. Myositis-specific auto-antibodies and muscle biopsies play key roles in diagnosis of HMGCR myopathy. Corticosteroids and immunosuppressants were first line therapy. Pediatric patients or patients with chronic course are usually refractory, and the efficacy of different combinations of immunosuppressants needs to be further investigated.