DMD and Duchenne muscular dystrophy: These have been used to block cryptic splice sites arising from exonic or intronic mutations, to induce exon skipping to overcome nonsense or frame-shift mutations, to promote therapeutically relevant exon inclusion, or to alter exon selection to generate specific isoforms.2 For Duchenne muscular dystrophy (DMD), antisense oligonucleotides are currently being tested in phase 3 clinical trials in patients carrying specific deletions, with the aim of forcing exon skipping to restore the open reading frame and recover a partially functional dystrophin.3