CFTR and cystic fibrosis: Cystic fibrosis (CF) is an inherited autosomal recessive disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) (Riordan et al., 1989), an epithelial anion channel that primarily conducts Cl− and HCO3− (Anderson et al., 1991; Poulsen et al., 1994).