Objective: To describe the main techniques used to detect skeletal muscle proteins and to discuss the results regarding the new classification of limb-girdle muscular dystrophies.
Material and methods: Over three hundred muscle biopsies with a suspected diagnosis of muscular dystrophy were immunostained for dystrophin, dystrophin-associated proteins, spectrin and utrophin. In one hundred and twenty of them, Western blot for different proteins was performed.
Results: Duchenne muscular dystrophy showed negative immunostaining and Western blot for dystrophin and dystrophin-associated proteins, and overexpression of utrophin. In Becker muscular dystrophy there is an abnormal dystrophin immunolabelling and molecular weight. Sarcoglycanopathies present decreased sarcoglycans and normal dystrophin. In some forms of congenital muscular dystrophy there is absence of merosin and alpha 2-laminin, with variable results on Western blot analysis.
Conclusion: The immunohistochemical analysis of several cytoskeletal and transmembrane proteins as well as Western blot analysis, are necessary to elaborate a correct diagnosis of dystrophinopathies, sarcoglycanopathies and the different forms of congenital muscular dystrophy [REV NEUROL 1999; 28: 154-8].