Splicing defects in the CFTR gene: Minigene analysis of two mutations, 1811+1G>C and 1898+3A>G

Abstract Background Cystic fibrosis is caused by mutations of the Cystic Fibrosis Transmembrane conductance Regulator gene (CFTR). Among the 1795 reported mutations, 221 (12.31%) are believed to affect pre-mRNA splicing. Nevertheless, not all splicing mutations have been demonstrated, by functional assays, to affect splicing in living cells. Methods We have used a minigene-based approach, coupled to site-specific mutagenesis, to analyze the effects of presumptive pre-mRNA splicing mutations. Results We show here that the intron 11 1811+1G>C and the intron 12 1898+3A>G mutations strongly affected CFTR pre-mRNA splicing. The encoded proteins are predicted to be defective, which would thus participate in the disease phenotype of carrier individuals. Conclusions These results further validate the minigene strategy for the study of presumptive splice mutations, and report unanticipated defects in splicing. Such assays should improve the analysis of genotype–phenotype correlations.