An 8-year-old boy presents with progressive proximal muscle weakness, pseudohypertrophy of calves, and markedly elevated CK (8000 U/L). Genetic testing reveals a frameshift deletion in exons 48–52 of the DMD gene causing a premature stop codon. Which molecular therapy targets this specific mutation mechanism?

• A Ataluren (stop-codon read-through therapy)
• B Eteplirsen (antisense oligonucleotide exon 51 skipping) ✓
• C Nusinersen (spinal muscular atrophy treatment)
• D Deflazacort (corticosteroid)

Explanation

Duchenne muscular dystrophy (DMD) with deletion of exons 48–52 disrupts the reading frame. Eteplirsen is an antisense oligonucleotide that skips exon 51, restoring the open reading frame and producing a truncated but partially functional dystrophin (similar to Becker MD). It is approved for exon 51-skippable mutations. Ataluren is used for nonsense (premature stop codon) mutations, not frameshift deletions. Nusinersen targets SMN2 in spinal muscular atrophy. Deflazacort slows progression but is not a targeted molecular therapy.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.