Abnormal desmin protein in myofibrillar myopathies caused by desmin gene mutations

Muscle proteins were extracted in various sodium dodecyl sulfate buffers fr om 6 patients with myofibrillar myopathy (MFM) and previously identified wi th mutations in the desmin gene (desmin myopathy, DesM), 6 with MFM without mutations, and 14 disease controls to search for alterations in biochemist ry and solubility of mutated desmin filaments. In the 1% posthigh-speed pel let fraction, desmin was detected with immunoblots only in DesM and not the other MFM. We conclude that mutant desmin forms insoluble aggregates that are specific for the DesM and can be detected with Western blots.