Personalized exon skipping strategies to address clustered non-deletion dystrophin mutations

Abstract

Antisense oligomer induced exon skipping is showing promise as a therapy to reduce the severity of Duchenne Muscular Dystrophy. To date, the focus has been on excluding single exons flanking frame-shifting deletions in the dystrophin gene, however, a third of all Duchenne Muscular Dystrophy causing mutations are more subtle DNA changes. Forty-five dystrophin exons are potentially frame-shifting and mutations in these will require the targeted removal of exon blocks to generate in-frame transcripts. We report that clustered non-deletion mutations in the dystrophin gene respond differently to different antisense oligomer preparations targeting the same dual exon block, the removal of which bypasses the mutation and restores the open reading-frame. The personalized nature of the responses to antisense oligomer application presents additional challenges to the induction of multi-exon skipping with a single oligomer preparation.

Antisense suppression of donor splice site mutations in the dystrophin gene transcript

“…This was not unexpected, as we have previously showed that small DMD mutations can influence oligomer‐mediated exon skipping outcomes (Forrest et al. ; Fragall et al. ).…”

“…As we have found with other small dystrophin gene lesions, it appears that the various dystrophin splice site mutations will require personalized oligomer design and exon skipping strategies on a case‐by‐case basis (Forrest et al. ; Fragall et al. ; Adkin et al.…”

AON-Mediated Exon Skipping for Duchenne Muscular Dystrophy

“…Skipping of an additional exon could restore the reading frame again. For example for an exon 18 duplication, successful skipping of exon 17 and both exon 18s resulted in restoration of the reading frame (Forrest et al, 2010). Successful skipping of multiple exon duplications has not yet been achieved .…”

Gene therapy: Progress in childhood disease

“…Specific destruction of mRNA species can also be used for applications such as antiviral therapy. Another developing strategy involves RNA editing, with an exciting example being synthetic oligonucleotide‐induced exon skipping, 17 which is being trialed for Duchenne muscular dystrophy 18 …”