Researchers develop DNA 'patch' for canine form of muscular...( Using a novel genetic technology tha...),Health

Using a novel genetic technology that covers up genetic errors, researchers funded in part by the National Institutes of Health have developed a successful treatment for dogs with the canine version of Duchenne muscular dystrophy, a paralyzing, and ultimately fatal, muscle disease.

The technology, known as "exon skipping" uses tailor-made snippets of DNA-like molecules as molecular "patches." These patches cover up mutant DNA sequences that code for making an important muscle protein. The mutant sequences occur in portions of the gene known as exons, which contain the information needed to make the muscle protein. By covering up the mutant regions, the DNA patches allowed the dogs to make an imperfectbut functionalversion of the protein, and significantly improve their muscle functioning.

Earlier studies showed that it was possible to inject the patches into the bloodstream of mice and deliver them throughout the animals' bodies. The current finding shows that the DNA patches could be delivered by injection throughout the entire body in a much larger animal than a mouse, raising the possibility that they might be successfully delivered throughout the body to human muscles as well. Moreover, the current study represents an advance over the earlier efforts in that it was able to use several different kinds of DNA patches. A combination of different patches, known as a cocktail, would be needed to treat most of the human cases of the disease, which can involve many different exons.

The canine version of Duchenne muscular dystrophy occurs naturally in dogs, and affects the same gene that is affected in the human form of the disease.

"This is a promising finding," said Duane Alexander, M.D., director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), one of the NIH institutes that provided partial funding for the study. "It's an important step toward realizing the goal of develo
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