Immunocytochemical study of cytoskeletal proteins in centronuclear myopathies.

The developmental status of muscle fibers was investigated in three cases of myotubular myopathy: one infant with the X-linked recessive form and two adult brothers with the autosomal, probably recessive, form of the disease. The presence of the developmentally regulated proteins desmin, vimentin and dystrophin was investigated by immunocytochemistry with the use of monoclonal antibodies. In the X-linked case, intense immunolabelling for vimentin and desmin was observed in the nuclear area of a great number of muscle fibers, while a few others showed sarcoplasmic dystrophin immunolabelling or were dystrophin-negative. In the adult cases, strong desmin immunoreactivity was observed, but only a few fibers labelled for vimentin. Dystrophin sarcolemmal immunolabelling was normal, but in some fibers dystrophin was observed in the area of the central nucleus. These findings are supportive of a maturational arrest of muscle fibers in the X-linked cases and possibly indicative of a similar mechanism in the adult form of centronuclear myopathy in these patients.