CFTR and cystic fibrosis: Cystic fibrosis (CF) is a genetic disorder due to mutations in the gene encoding the CF transmembrane conductance regulator (CFTR), a kinase-activated and ATP-gated channel protein controlling the transport of chloride (Cl−) and bicarbonate (HCO3-) anions across mucosal surfaces, including those at the airways, and hence, the composition of the periciliary airway liquid [1–4].