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Gene addition of micro-dystrophin improves Duchenne muscular dystrophy symptoms in dogs

Researchers from the University of Nantes and Royal Holloway have been able to relieve symptoms of muscular dystrophy in affected dogs. Golden retriever muscular dystrophy (GRMD) dogs have naturally occurring muscular dystrophy and are normally not anticipated to live longer than 6 months. The disease is similar to Duchenne muscular dystrophy (DMD) in humans, which affects 1:5000 boys. DMD patients experience serious muscle wastage for which only palliative treatments exist. The disease is caused by a mutation in the dystrophin gene, which is essential for the function and stability of muscle fibres.   

In this study, the researchers used a shortened form of the dystrophin gene, micro-dystrophin. Contrary to full-length dystrophin, micro-dystrophin is small enough to be packaged in a recombinant AAV virus that transduces skeletal and cardiac muscle cells. Dogs injected with the virus systemically showed a clear, high-level expression of micro-dystrophin and an overall recovery of muscle function. The effect of the therapy can be readily observed in a video in the Telegraph article linked to below. The dogs were observed for 2 years and showed symptom stabilisation and, notably, no clear side-effects of the treatment. Contrary to previous work, the researchers did not resort to immunosuppressive treatment before or after the virus administration. The authors conclude that the study paves the way for human clinical trials and that treatment with microdystrophin is a potential therapy for all DMD patients, regardless of the exact mutation in their dystrophin gene. 

Original article: Nature Communications

Digest for a general audience: Telegraph