The prevalence and clinical characteristics of anti-HMGCR (anti-3-hydroxy-3-methyl-glutaryl-coenzyme A reductase) antibodies in idiopathic inflammatory myopathy: an analysis from the MyoCite registry

Six Years Follow-Up of an 11-Year-Old Girl with Anti-HMGCR Myopathy

Anti-HMGCR myopathy is decribed as an immune-mediated necrotizing myopathy which is characterised by subacute, progressive proximal muscle weakness and elevated creatine kinase (CK) level. In pediatric population, anti-HMGCR myopathy has been reported solely as small case reports, albeit rare. Although treatment consensus has not yet been established, proper treatment with several immunomodulators to include IVIg can show remarkable improvement. We report an 11-year-old-girl diagnosed with anti-HMGCR myopathy with 6 years of follow-up.

Anti-HMGCR immune-mediated necrotising myopathy: Addressing the remaining issues

The discovery of autoantibodies directed against the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) enzyme has defined a sub-set of immune-mediated necrotising myopathy (IMNM) which is strongly associated with exposure to statin medications. Although understanding of anti-HMGCR IMNM has grown considerably with the reporting of multiple cohorts in North America, Europe, Asia and Oceania, there remain many unanswered questions. The true incidence of anti-HMGCR IMNM is not known and heterogeneity of phenotype and treatment response within this autoantibody sub-group is being increasingly recognised. Statin-naïve adults and juvenile patients with anti-HMGCR potentially share characteristics distinct from statin-exposed patients, alluding to unique pathogenesis. Conflicting data exists on whether malignancies are associated with anti-HMGCR and further clarification is required to determine the degree of cancer screening required. Treatment approaches to anti-HMGCR IMNM are heterogeneous but generally highlight the efficacy of intravenous immunoglobulin. Even with multimodal immunosuppression, patients with anti-HMGCR remain prone to relapse, with younger patients generally manifesting more refractory disease. In this Review, we aim to summarise the current literature on anti-HMGCR and discuss the remaining issues.

Refractory Statin-Induced Immune-Mediated Necrotizing Myositis: Challenges and Perils in Its Management

Statin or 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibitor is widely used and plays a vital role in the management of cardiovascular and cerebrovascular diseases. Statin is generally safe and its side effects are mostly mild and self-limiting. Immune-mediated necrotizing myositis (IMNM) is a rare and serious side effect characterized by the presence of anti-HMGCR inhibitor and myositis. Long-term immunosuppressive therapy is often required to manage it, and in refractory cases, the treatment can be very challenging. We report the case of a 55-year-old female with underlying diabetes mellitus and hyperlipidemia who developed refractory statin-induced IMNM despite being administered prednisolone, methotrexate, azathioprine, and immunoglobulin. After the introduction of rituximab, steroids were able to be tapered down to the lowest maintenance dose. Unfortunately, the patient subsequently succumbed to severe coronary artery disease (CAD) likely caused by the long-term steroid therapy, highlighting the difficulty and complications associated with the treatment of IMNM, especially in patients with cardiovascular risk factors.