[Duchenne muscular dystrophy pathophysiology]

Dystrophin is a large cytoskeletal protein located at the plasma membrane in both muscle and non-muscle tissues, which mediates interactions between the cytoskeleton, cell membrane, and extracellular matrix. Dystrophin is a key component of multiprotein complexes (dystrophin- associated glycoprotein complex, or DGC). It is also involved in many intracellular cascades affecting membrane proteins such as calcium channels, or various signalisation pathways. In Duchenne Muscular Dystrophy, both dystrophin and DGC proteins are missing. This induces excessive membrane fragility and permeability, dysregulation of calcium homeostasis, oxidative damage, which in turn favour muscle cell necrosis. The latter is initially followed by regeneration. With age, the regenerative capacity of the muscles appears to be exhausted and muscle fibres are gradually replaced by connective and adipose tissue.