Anti-HMGCR IMNM is considered to be among the least frequent subtypes of idiopathic inflammatory myopathies, estimated to represent around 12% after excluding inclusion body myositis (IBM) (3).The identification of anti-HMGCR antibodies dates back to 2010, when Christopher-Stine et al. The gene discussed is HMGCR; the disease is inclusion body myositis.