MSTN and Duchenne muscular dystrophy: Several clinical trials have tested drugs that inhibit myostatin, an activator of the TGFβ-Smad2/3 pathway, in an attempt to mitigate muscle atrophy at the receptor level (NCT02515669, NCT02310763) [23]; however, the clinical efficacy of anti-myostatin drugs has not been shown; this underscores the complexity of dystrophic signaling in DMD.