MSTN and muscular dystrophy: TGF-β signalling associated with genes upregulated in clinically severe FSHD and is well studied in muscular dystrophy, particularly myostatin, which limits muscle growth via mechanisms directly relevant to FSHD, including direct suppression of PAX7 and activation of p38.63 Targeting TGF-β has been considered as a therapy for FSHD via the small-molecule inhibitor ACE-083.