FIGURE 1.

DMD pathophysiology and levels of action for the different compounds discussed in the paper. Mutations in the dystrophin gene lead to absence of functional dystrophin protein in muscle cells and destabilisation of the dystrophin-associated complex at the sarcolemma. This leads to increased susceptibility of the membrane to mechanical stress and ischaemia leading to increased membrane permeability, disturbed cellular signalling, and higher intracellular calcium levels causing activation of intracellular proteases. Mitochondrial dysfunction and increased production of reactive oxygen species contribute to DMD pathophysiology. These trigger a cycle of cell necrosis, chronic inflammation, and decreased muscle regenerative capacity. Ultimately, muscle fibres are lost and replaced by connective and adipose tissue resulting in muscle dysfunction. The different levels of action for the compounds discussed in the paper are indicated in red colour.