Desmin is a protein that in humans is encoded by the DES gene. Desmin is a subunit of intermediate filaments in cardiac muscle, skeletal muscle and smooth muscle tissue. In cardiac muscle, desmin is present in Z-discs and intercalated discs and regulates sarcomere architecture. Desmin-related myofibrillar myopathy (DRM or desminopathy) is a subgroup of the myofibrillar myopathy diseases and is the result of a mutation in the gene that codes for desmin which by changing the protein structure prevents it from forming protein filaments, and rather, forms aggregates of desmin and other proteins throughout the cell. Desmin has been evaluated for role in assessing the depth of invasion of urothelial carcinoma in TURBT specimens.