Gene patches treat muscular dystrophy
Researchers have developed a new approach in the search for treatments for Duchenne muscular dystrophy (DMD). Based on the principle of concealing the genetic errors that cause the disease, the treatment has been successful in dogs with the canine version of DMD.
DMD is one of nine versions of muscular dystrophy and is caused by a faulty protein, produced by a mutated dystrophin gene. It is a paralysing and often fatal muscle-wasting disease. Associated with the X chromosome, it affects only boys, starting very young (between 2 and 6 years) and almost always resulting in early death. As yet there is no treatment, but strains of mice and dogs suffer ‘naturally’ from the disease, allowing scientists to study it in more depth.
The new treatment is based on existing technology known as exon-skipping, which uses sections of DNA-like molecules as ‘patches’ to conceal the mutations in dogs. Because mutation occurs in different places in the dystrophin gene, scientists tried multiple patches called morpholinos. They succeeded in restoring protein and muscle function. Previous studies have successfully injected morpholinos into the bloodstream of mice; this study suggests morpholino injection can be successful in much larger animals.
The results open up the possibility of using morpholinos against the multiple mutations that occur in human DMD, using injection as the method of delivery. However, further research is needed as large doses of the patches were required. This would be expensive and could be toxic. Also, the treatment did not effectively prevent or slow heart muscle deterioration, so a more specific delivery system may be needed.
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