Diagnosis of Statin-Induced Necrotizing Myopathy: Contribution of Anti-HMGCR Antibodies

Over the last few years, several cases of statin-induced necrotizing myopathy have been described. This myopathy is characterized by the necrosis of muscle fibers and the presence of anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibodies. Although the diagnosis of myopathies relies on muscle biopsy, which is considered the gold-standard, the search for autoantibodies has proved to be an essential contribution to the diagnosis of immune-mediated myopathies. The detection of anti-HMGCR antibodies in the patient???s serum can be performed by enzyme immunoassays, and more recently, by imunofluorescence. As for the latter, the detection of anti-HMGCR antibodies is performed on tissue sections by indirect immunofluorescence and is characterized by a typical fluorescence pattern called ???HMGCR Associated Liver IFL Pattern???. The authors present two case reports that show the importance of diagnosing statin-induced necrotizing myopathy as quickly as possible and the contribution of anti-HMGCR antibody detection for the diagnosis.