They did this in in embryos and I read a comment somewhere that it would still be a long way to apply this to other groups.
I can't judge it without any medical background, but isn't what companies like bluebird bio do much more advanced, as in: they work towards curing thalassemia in childs and adults and not just embryos?
I mean, if people just did a PID and checked for thalassemia, they could guarantee that the child is born without thalassemia, so the most interesting research is that done on people that are already born with it.