> CHARMs, however, work further upstream, turning off the gene that codes for the faulty protein so that the protein never gets made in the first place. [...] In a person who hasn’t yet developed symptoms, removing the protein should prevent disease altogether.
That said, it may still be relevant as a helpful therapy for someone already infected, if the accidental production of "fresh" prions--happening in parallel in all cells--is a much bigger problem than an existing prion floating around and catalyzing neighbors:
> Testing in mice showed that ZFP-guided CHARMs could eliminate more than 80 percent of the prion protein in the brain, while previous research has shown that as little as 21 percent elimination can improve symptoms.
A corrections: a prion (the disease agent) is believed to be a self replicating protein fold, so it needs a source protein ("prion protein", aka PrP, one word) to feed the folding.
Now, although the evidence is pretty solid that the fold is the infectious agent, there's a lot of unanswered questions: we can try to make prions in the lab but iiuc no one has made a fiber of PrP in the lab without seeding from an infectious sample that itself was infectious.
Moreover, a lot of related Alzheimer's research has come under intense scrutiny recently[0], so much so that the viral hypothesis of Alzheimer's is now dominant and no longer the "prion-like hypothesis", so, it's possible that the self-propagating protein fold is not the infectious agent for prion disease either.
If it is, then it's likely that turnjng down PrP in the brain will slow or even reverse the disease. The PrP fibers probably can be degraded, if very slowly, and turning off the spigot of source material for the fold will push the equilibrium in the other direction
[0] see marc tessier levigne (current CEO of AI/biotech form Xaira)'s firing?resigning? from stanford due to fraudulent data in his lab