"Editing muscle cells lies somewhere in the middle of the difficulty scale. Genetically, it’s a good candidate. Even with just a delete key, Olson says, up to 80 percent of muscular dystrophy cases could be treated. Initially, the editing treatment he’s working on will target a hot spot in the dystrophin gene—exon 51, in which Editas has also signaled an interest. Deleting that exon could treat about 13 percent of Duchenne cases.
The most significant unknown is whether it will be possible to edit enough muscle cells and make enough dystrophin in a human body. “I think this represents the most promising strategy,” says Olson. “But the thing that has to go right is that it has to be efficient.” Muscles, including the heart, glutes, and biceps, make up 40 percent of a person’s body mass—billions and billions of cells. So far, in his mice, Olson has succeeded in producing dystrophin in 5 to 25 percent of muscle fibers. It’s half calculation and half speculation, but he thinks that editing 15 percent of the muscle cells in a boy will be enough to slow, if not halt, muscular dystrophy.
Actually this article is a very good overview. I actually read it months ago and forgot about it. This Olsen guy from Univ. of Texas is working with our our collaborator Mendel at Children's Hospital in Ohio as weel..
https://
www.technologyreview.com/s/602491/can-crispr-save-ben-dupree/
This was from October 2016. It says Mendel was about to start in on monkeys and that a human clinical trial could start in two years - October 2018 - ideally. So it's been 9 months since then and I wonder how it's going with the monkeys? Perhaps this would be the likely person/persons to partner with once we see how it's going with the monkey trials.