Anti-HMG CoA reductase antibody is most closely linked to which condition?

• A. Rheumatoid arthritis
• B. SLE
• C. Statin-induced myopathy
• D. Gout

Answer: (C)

Anti-HMG-CoA reductase antibodies point to a statin-triggered autoimmune myopathy. HMG-CoA reductase is the enzyme targeted by statins, and in some individuals the immune system develops antibodies against this enzyme, leading to a progressive proximal muscle weakness with a markedly elevated CK. This autoimmune necrotizing myopathy often persists or worsens after stopping the statin and typically requires immunosuppressive treatment rather than simply withdrawing the drug. The muscle biopsy characteristically shows necrotic fibers with little inflammatory infiltrate, which helps distinguish it from other inflammatory myopathies. Because these antibodies are specifically associated with a statin-related autoimmune process, they best explain a link to statin-induced myopathy rather than to rheumatoid arthritis, SLE, or gout.