A 61-year-old woman presented progressive distal weakness and wasting of her upper limbs spreading to the shoulder girdle and to the neck muscles. Creatine kinase, cerebrospinal fluid, spinal X-ray and spinal nuclear magnetic resonance were normal. Electromyography showed myopathic alterations. Muscle biopsy showed abundant rods in many fibres. Prednisone 75 mg/die for two months did not modify the symptoms.