Five new cases and 30 others from the literature were characterized by the clinical triad of progressive external ophthalmoplegia, atypical pigmentary degeneration of the retina, and heart block. The syndrome is sporactic, not hereditary, and begins by the age of 20 years. In many cases there is other evidence of widespread neurological disorder, implicating specific areas: cerebellum; auditory and vestibular systems; skeletal muscle; and, less often, intellectual function or corticospinal tracts. Short stature and delayed sexual maturation are also frequent. The CSF protein content is almost always greater than 100 mgidl. Spongioform encephalopathy was found in 4 postmortem examinations. In all cases so examined, muscle mitochondria were abnormal.The constancy of these manifestations suggests that the disorder is a true entity, not an artificial subclass of the large group of disorders associated with ophthalmoplegia. Several characteristics suggest that the disorder of neuronal and muscle metabolism is induced by persistent viral infection.

No abstract

Five patients, 4 men and 1 woman, had adult-onset and slowly progressive weakness. There was distal wasting in 2, hepatomegaly in 3, and congestive heart failure in 2. Electromyography showed a mixed pattern with abundant fibrillations. Serum creatine phosphokinase was increased 5- to 45-fold. Blood glucose failed to respond to epinephrine or glucagon, and venous lactate did not rise after ischemic exercise. Muscle biopsy showed vacuolar myopathy affecting both fiber types. By electron microscopy the vacuoles corresponded to large pools of glycogen not limited by a membrane. Glycogen concentration was 3 to 5 times normal in muscle and 7 to 21 times normal in erythrocytes. In the presence of iodine, muscle glycogen showed a spectrum characteristic of phosphorylase-limit-dextrin. Debrancher activity was measured by a spectrophotometric assay and by a radioactive reverse reaction. The activity was lacking in muscle and erythrocytes of 4 patients according to both assays; in 1 patient the reverse reaction was not impaired. Though previously reported in only 5 patients, debrancher deficiency myopathy may not be rare and should be considered in the differential diagnosis of adult-onset hereditary myopathies.