It works because many cases of muscular dystrophy are caused by mutations in the dystrophin gene (incidentally, one of the longest genes in the body) that make the entire genetic code for the protein shift by one letter.
Locating genes that code for more than one protein could allow Rosetta to find drug targets in tissues that were not considered drugable by finding previously unknown exons in known genes, Friend says.
You may have the DNA code of a gene, but that doesnt mean you know much about that protein it controls what it does, or even whether it is present in mature individuals.