However, unlike the airways, the paracellular pathway in the absorptive duct has little intrinsic Cl− permeability in both normal and CF glands [208, 213] and due to high anion conductance of the apical and basolateral membranes of the duct cells (due to active CFTR), Cl− moves transcellularly. The gene discussed is CFTR; the disease is cystic fibrosis.