Methods for the assessment of ssODN-mediated gene correction frequencies in muscle cells

The past decade has seen the development of new technologies capable of editing the genome that have naturally led to exploring their therapeutic application for the treatment of many disorders. Among those, Duchenne muscular dystrophy (DMD) represents an ideal candidate for gene editing primarily due to the large size of dystrophin, the gene responsible for the disease, which limits the use of gene replacement approaches. Critical in the evaluation of the efficacy of the treatment is the development of a method that can accurately quantitate the frequencies of gene repair obtained in the dystrophin gene at both the genomic level as well as the mRNA level. The mdx (5cv) mouse model of DMD offers an ideal system to precisely determine the frequencies of gene repair. Here we describe the methods used for determining those frequencies and the limitations associated with the use of gene correction for the treatment of DMD. Clinical approaches to muscle disorders using ssODNs will heavily rely on the optimization of the technology and will have to take into consideration the safety, efficacy and cost of the procedure in vision of systemic delivery of the therapeutic treatment.