Familial megaconial myopathy: A real nosologic entity - Clinical and histopathologic studies in two siblings

The most prominent ultrastructural feature of muscle tissue in two siblings with a childhood-onset myopathy was the presence of giant mitochondria of up to 4 μm in length. The mitochondria had no tendency to aggregate and kept their normal localization among the myofibrils. Such a megaconial myopathy was first described by Shy and Gonatas (1964), In our family two members had the disease and consanguinity between their parents was present. These data suggest that megaconial myopathy might be a real nosologic entity genetically transmitted as an autosomal recessive trait.