Myofibrillar myopathies

Purpose of review: The aim of this communication is to provide an up-to-date overview of myofibrillar myopathies (MFMs). Recent findings: The most important recent advance in the MFMs has been the identification of mutation in Bag3 (Bcl-2-associated athanogene-3) as a new cause of MFM. Although, the typical clinical manifestations of MFMs are slowly progressive weakness, the patients with Bag3opathy may have had a rapidly progressive and more severe phenotype. Summary: Several MFM disease genes have recently been recognized. The identified disease proteins (desmin, αB-crystallin, myotilin, Zasp, filamin C, and Bag3) interact with components or with chaperones of the Z-disk. In each case the molecular defect leads to a largely stereotyped cascade of structural perturbation of the muscle fiber architecture.