Centronuclear Myopathy: A Light and Electron Microscopic Study and a Review of the Literature

Summary The clinical and histological features of a nine‐year‐old Japanese boy with a centro‐nuclear myopathy was described, who had been suffering from non‐progressive ble‐pharoptosis and generalized muscular weakness since the first months of life. The muscle biopsy of the patient showed a moderate variation in the diameter and a presence of numerous central nuclei frequently with a surrounding clear zone in 66.8% of the muscle fibers. Electron microscopically the changes of the myofibrils were minimal. There were aggregates of glycogen granules and mitochondria in a clear zone around the central nuclei. A review of the 31 total cases showed a lack of uniformity in the age of onset, genetics and clinical features, despite of the histological resemblance as the existence of central nuclei in a large proportion of muscle fibers. The question of whether more than one disease entity is included was raised.