CFTR and cystic fibrosis: Nonetheless, these results, combined with the analysis of total CFTR mRNA (Figs. 4F and 5F), suggest that ASO-23AB may be more effective at inducing exon 23 skipping in CFTR-W1282X RNA, which could be advantageous in treating CF patients compound heterozygous for CFTR-W1282X and another CFTR mutation less responsive to modulator treatment.