A 63 year-old man had a past medical history of diabetes and hypertension, did not smoke or drink alcohol, and had no relevant family history. Over the course of several months he developed left leg weakness and difficulty climbing stairs. He denied other symptoms including fever, sweats, chills, shortness of breath or chest pain. On general examination he had no adenopathy or hepatosplenomegaly. Neurological examination revealed focal weakness of the left hip flexor but was otherwise normal. Electromyography (EMG) showed a myopathic process. A biopsy was performed on an unspecified leg muscle.