Genetic researchers at Children’s National Medical Center and the National Center of Neurology and Psychiatry in Tokyo published the results of the first successful application of “multiple exon-skipping” to curb the devastating effects of Duchenne muscular dystrophy in an animal larger than a mouse.
Multiple exon-skipping employs multiple DNA-like molecules as a “DNA band-aids” to skip over the parts of the mutated gene that block the effective creation of proteins. Duchenne muscular dystrophy that strikes 1 of every 3,500 boys born in the United States and worldwide each year. (So almost one million people have it.)
“Exon-skipping” employs synthetic DNA-like molecules called antisense as a DNA bandaid to skip over the parts of the gene that block the effective creation of dystrophin. Because the gene’s mutation could affect any of its 79 exons and sometimes more than one single exon at a time, scientists employed a “cocktail” of antisense called morpholinos to extend the range of this application. By skipping more than a single exon, this so-called DNA band-aid becomes applicable to between 80 and 90 percent of Duchenne muscular dystrophy patients.
Systemic treatment of the majority of Duchenne dystrophy will require multiple sequences to be delivered in the blood, and this study also is the first proof-of-principle of multiple exon-skipping in any organism,” Shin’ichi Takeda, MD, another senior author, said. “In order to realize that promise in human trials, it also will be important to re-evaluate current measures of toxicity, efficacy, and marketing that ensure both safety for the patient, as well as rapid development and distribution of life-saving drugs.