High-efficiency repair of the ΔF508 mutation by HDR was reported in primary CF basal epithelial cells in vitro by electroporation with liposomal Cas9 and sgRNA, while the DNA template was delivered by AAV6, with a repair efficiency of approximately 40%, but also an indel frequency of approximately 38% in the non-corrected allele, most of which would generate CFTR-inactivating frameshifts and deletions.46 Here, CFTR is linked to cystic fibrosis.