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

Abstract

We describe two donor splice site mutations, affecting dystrophin exons 16 and 45 that led to Duchenne muscular dystrophy (DMD), through catastrophic inactivation of the mRNA. These gene lesions unexpectedly resulted in the retention of the downstream introns, thereby increasing the length of the dystrophin mRNA by 20.2 and 36 kb, respectively. Splice-switching antisense oligomers targeted to exon 16 excised this in-frame exon and the following intron from the patient dystrophin transcript very efficiently in vitro, thereby restoring the reading frame and allowing synthesis of near-normal levels of a putatively functional dystrophin isoform. In contrast, targeting splice-switching oligomers to exon 45 in patient cells promoted only modest levels of an out-of-frame dystrophin transcript after transfection at high oligomer concentrations, whereas dual targeting of exons 44 and 45 or 45 and 46 resulted in more efficient exon skipping, with concomitant removal of intron 45. The splice site mutations reported here appear highly amenable to antisense oligomer intervention. We suggest that other splice site mutations may need to be evaluated for oligomer interventions on a case-by-case basis.

Altérations de l’épissage et maladies rares

“…La dystrophie musculaire de Duchenne est une maladie neuromusculaire caractérisée par une atrophie et une faiblesse musculaire progressive due à une dégénérescence des muscles. La maladie est liée à des mutations affectant l'épissage du gène de la dystrophine [15]. La mucoviscidose est la plus fréquente des maladies génétiques touchant les enfants dans les populations occidentales.…”

The emperor's new dystrophin: finding sense in the noise

“…This is an unacceptable situation. In a forwardlooking approach, some groups have developed AOs for multi-exon skipping and to address uncommon deletions, duplications, and a range of other non-deletion DMD mutations [22,[109][110][111][112][113][114].…”

Investigational treatments and therapeutic targets in Becker muscular dystrophy

“…Furthermore, splicing modulation with antisense oligonucleotides has been tried for acquisition of functional mRNA [48,49]. Therefore, the knowledge of how to modulate splicing could be transferred to the development of BMD treatments.…”