Name an FDA-approved exon-skipping therapy for DMD and its target exon.

• A. Eteplirsen targeting exon 51
• B. Golodirsen targeting exon 53
• C. Viltolarsen targeting exon 53
• D. Casimersen targeting exon 45

Answer: (A)

Exon skipping therapies use an antisense molecule to bind a specific exon in dystrophin pre-mRNA and cause that exon to be skipped during splicing. This can restore the reading frame so a truncated but functional dystrophin protein is produced in patients with certain DMD mutations. Eteplirsen, FDA-approved, targets exon 51, making it a correct example: it is approved for patients whose mutation is amenable to skipping exon 51 and directly specifies exon 51 as the target. Other options target different exons (53 or 45) and are used for other mutation groups, but the stated pairing here is eteplirsen with exon 51.