The first approved drug, i.e. eteplirsen (Exondys51), is a PMO‐based splice‐switching ASO that interacts specifically with DMD exon 51, and is used in DMD patients with dystrophin deletions amenable to exon 51 skipping (~14% of patients) (Cirak et al,2011). The gene discussed is DMD; the disease is Duchenne muscular dystrophy.