CFTR and cystic fibrosis: The deletion of a phenylalanine at position 508 (F508del) is by far the most prevalent CF-causing mutation, occurring in 80–85% of CF cases worldwide [2]; however, more than 2100 CFTR genetic variants have been reported to date (http://www.genet.sickkids.on.ca/, accessed on 22 December 2022), most being presumably pathogenic and leading to a broad range of phenotypes, from classical CF to mild disease symptoms (https://cftr2.org/, accessed on 22 December 2022).