Anti-signal Recognition Particle Necrotizing Autoimmune Myopathy: An Atypical Presentation

Necrotizing autoimmune myopathy (NAM), also known as necrotizing autoimmune myositis, is a heterogeneous group of diseases characterized by the presence of necrotic muscle fibers on biopsy, elevated creatine kinase (CK) levels, an abnormal electromyogram (EMG) result, and the associated antibodies. The anti-signal recognition particle (anti-SRP) and the anti-3-hydroxyl-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) antibodies are the two most prevalent antibodies identified with NAM. NAM is a rare disease that typically affects middle-aged Caucasian women. In this case report, we present the diagnosis of anti-SRP NAM in a middle-aged African American male. This case report displays the atypical presentation of NAM outside of the typical patient population as well as the need for additional research to determine the pathogenesis and the precise role of anti-SRP antibodies in NAM.