CFTR and cystic fibrosis: Although heterologous Slc26a9 expression influences the transport activity of endogenous CFTR in a variety of airway cell culture systems [6, 26, 29] and a recent publication described the presence of Slc26a9 variants in two patients with bronchiectasis [5], a genome-wide association study revealed an increased incidence of meconium ileus in CF infants with Slc26a9 polymorphisms [41], a susceptibility to CF diabetes [7, 38] but not of severity of CF lung disease [7].