In addition, the defective CFTR prevents chloride to follow sodium influx, inducing chloride to be retained in the ASL (Krouse, 2001), as the more recently identified alternative chloride channels TMEM16A and SLC26A9 do not appear to counterbalance impaired anion transport in CF patients (Mall and Galietta, 2015; Martin et al., 2018). Here, CFTR is linked to cystic fibrosis.