Immunoblot as a potential diagnostic tool for myofibrillar myopathies

Myofibrillar myopathies (MFMs) are a group of inherited or sporadic neuromuscular disorders morphologically characterized by foci of myofibril dissolution, disintegration of the Z-disk and insoluble protein aggregates within the muscle fibers. The diagnosis is based on muscle biopsy. Light and electron microscopy has a central role in the diagnostic work-up and immunohistochemistry shows abnormal deposition of several proteins including αB-crystallin, desmin and myotilin. In contrast immunoblotting does not have any diagnostic value because it does not highlight differences in the amount of involved proteins. We investigated the pattern and level expression of desmin, αB-crystallin, myotilin and ZASP in muscle of seven patients with MFMs by immunoblotting after SDS-PAGE and 2D-PAGE using two different solubilizing solutions, one RIPA buffer and the other urea-containing buffer. Our data demonstrated that urea-containing buffer improves the solubilization and recovery of desmin, αB-crystallin, myotilin and ZASP as compared with RIPA buffer and that the total content of these proteins is increased in muscle of patients. The present results provide evidence that immunoblotting is an additional tool for confirming diagnosis of MFMs. This article is protected by copyright. All rights reserved.