CFTR and cystic fibrosis: The most prevalent CFTR mutation was discovered almost 30 years ago; it was the deletion of a phenylalanine at position 508 (ΔF508) (Kerem et al., 1989; Riordan et al., 1989), which affects ∼80% of CF patients worldwide (Bobadilla et al., 2002; Sosnay et al., 2013).