The trick right now is in knowing exactly what gene to express. It's like the Ionis Huntington's trial, just one well-known gene to suppress (albeit in cerebrospinal fluid, so the stage 1 trials were interesting). And of course, the first-wave funding will go to stuff that absolutely, positively will kill a person stone dead.

As soon as there's multiple targets it gets more complicated. Familial Hypercholesteroleamia could be any of three genes in it's least complex setup. I wouldn't be surprised to see a scam "therapy" marketed for it by the end of the year...