CFTR and cystic fibrosis: For example, P. aeruginosa infection is less prevalent in patients with CFTR mutations associated with residual CFTR function (Burgel et al., 2010) and variants in dynactin 4 have been associated with late occurrence of the first P. aeruginosa culture in CF patients (Emond et al., 2012; Viel et al., 2016).