The announcement was made yesterday at the annual meeting of the American Society of Gene & Cell Therapy and simultaneously published in the New England Journal of Medicine. I wrote about it for the Italian edition of Scientific American, but this story is worth seeing and reading.
PS: Before KJ was treated for his metabolic disorder, there was the case of Terry Horgan, who had muscular dystrophy. Unfortunately, the personalized treatment for him came too late, and he did not survive an adverse reaction. So yes, we can say that KJ represents a first: the first time genome editing was used early, rapidly, and tailored enough to truly offer hope for a happy ending.