SUBSARCOLEMMAL EXPRESSION OF UTROPHIN IN NEUROMUSCULAR DISORDERS - ANIMMUNOHISTOCHEMICAL STUDY OF 80 CASES

The immunohistochemical expression of utrophin in 80 muscle biopsies f rom patients with dystrophinopathies and other neuromuscular disorders is reported. All biopsy specimens were routinely studied by a battery of 12 histoenzymatic techniques, and immunohistochemistry was perform ed for spectrin, three domains of dystrophin and two domains of utroph in. Abnormal utrophin expression was observed in all dystrophinopathic muscles compared with normal controls or biopsy samples from several other muscular diseases. Inflammatory myopathies presented abnormal ov erexpression of utrophin and an abnormal dystrophin immunolabeling pat tern. This overexpression of utrophin appears to be directly related t o the decrease in dystrophin. We conclude that the study of utrophin i s important for the histological interpretation and differential diagn osis of dystrophin-related muscular disorders.