The main defect in CF is a dysfunctional CF transmembrane conductance regulator (CFTR) protein coded by the CFTR gene localized on the long arm of the seventh chromosome.1 Despite the early discovery of the gene in 1989 and progress in understanding the pathophysiology of the disease, it was not until 2012 that the first substance to correct the basic defect in CF, ivacaftor, was approved.2, –4 Since then, several mutation-specific CFTR modulators have been developed with a wide variation in efficacy. Here, CFTR is linked to cystic fibrosis.