Finally, when we undertook western blot analyses followed by quantitation of bands assigned to PrPC, we observed that steady-state levels of this protein were reduced by 13% in 9P31-SlugCas9-HF-MM1 treated mice when compared to mouse brains transduced with the negative control 9P31-EGFP vector (Fig 7D). Here, PRNP is linked to hydrops fetalis.