CFTR and cystic fibrosis: Crucially, the enhanced edit-to-indel ratio of the PE strategies developed in this study, compared with the use of Cas9 nuclease, results in unedited alleles predominantly encoding the unmodified F508del CFTR protein that remains druggable by CF small-molecule correctors and potentiators, unlike the frameshifted CFTR alleles from the much higher frequency of nuclease-mediated indel byproduct formation that probably generate truncated CFTR proteins that cannot be rescued by small-molecule drugs.