Affiliations: [a] The Center for Gene Therapy, Nationwide Children’s Hospital, The Ohio State University, Columbus, OH, USA
| [b] Perron Institute for Neurological and Translational Science, Center for Comparative Genomics, Murdoch University, Perth, Australia
| [c] Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| [d] Department of Neurology, The Ohio State University, Columbus, OH, USA
Correspondence:
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Correspondence to: Kevin M. Flanigan, MD, Center for Gene Therapy, The Research Institute, WA3014, Nationwide Children’s Hospital, 700 N. Children’s Drive, Columbus, OH 43205, USA. Tel.: +1 614 355 2947; Fax: +1 614 722 3273; E-mail: kevin.flanigan@nationwidechildrens.org.
Abstract: Background:Exon skipping strategies in Duchenne muscular dystrophy (DMD) have largely been directed toward altering splicing of exons flanking out-of-frame deletions, with the goal of restoring an open mRNA reading frame that leads to production of an internally deleted but partially functional dystrophin protein. Objective:We sought to apply exon skipping to duplication mutations, assuming that the inherently limited efficiency of antisense oligonucleotide-induced exon skipping would more frequently skip a single copy of a duplicated exon, rather than both and result in significant amounts of wild-type DMD mRNA. Methods:We tested this hypothesis in fibroblast cell lines derived from patients with a variety of single or multiple exon duplications that have been modified to allow transdifferentiation into a myogenic lineage. Results:Using a variety of 2’O-methyl antisense oligonucleotides, significant skipping was induced for each duplication leading to a wild-type transcript as a major mRNA product. Conclusions:This study provides another proof of concept for the feasibility of therapeutic skipping in patients carrying exon duplications in order to express wild-type, full-length mRNA, although careful evaluation of the skipping efficiency should be performed as some exons are easier to skip than others. Such a personalized strategy is expected to be highly beneficial for this subset of DMD patients, compared to inducing expression of an internally-deleted dystrophin.
