ADULTS WITH EOSINOPHILIC MYOSITIS AND CALPAIN-3 MUTATIONS

Abstract

A recent report found that six patients who presented with eosinophilic myositis in childhood actually had a calpainopathy (LGMD 2A).1 I have encountered two patients previously diagnosed with adult-onset eosinophilic polymyositis who had mutations in the calpain-3 gene ( CAPN3 ). ### Case reports. #### Case 1. A 22-year-old woman presented with a 1-year history of progressive arm and leg weakness and elevated serum creatine kinase (CK) levels as high as 5,528 U/L. There was no family history of myopathy. She was initially evaluated elsewhere and a quadriceps muscle biopsy was interpreted as an inflammatory myopathy with prominent eosinophilic infiltrates. There was no peripheral eosinophilia. She was treated with prednisone, azathioprine, methotrexate, IV immunoglobulin, and rituximab without improvement. She was referred to me for management of her myositis. Manual muscle testing revealed the following Medical Research Council (MRC) grades: neck flexion 4−/5, neck extension 4/5, deltoids, biceps, and triceps 4/5, wrist extension 4+/5, wrist flexors and fingers 5/5, hip flexion/extension/abduction 2/5, knee flexion 3/5, knee extension 4+/5, ankle dorsiflexion and plantar flexion 4+/5. There was no facial weakness, muscle atrophy, or hypertrophy. Serum CK was 845 U/L. Review of her outside muscle biopsy slides demonstrated many necrotic and …