It is used exclusively in splice-switching oligonucleotides (SSOs) targeting different exons of dystrophin mRNA for the treatment of Duchenne muscular dystrophy (DMD), specifically in the drugs Exondys 51, Vyondys 53, Viltepso, and Amondys 45 [313, 314]. The gene discussed is DMD; the disease is Duchenne muscular dystrophy.