CFTR and hereditary disease: Cystic fibrosis (CF) is one of the most common autosomal recessive genetic disorders in the Caucasian population, with an incidence of approximately 1 in 4000–5500 live births in the Netherlands.[1,2] This life-shortening disease is caused by mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene, which encodes the CFTR protein, expressed as a chloride ion channel at the apical membranes of secretory epithelia.