Finally, among the proteins less abundant in DHD as compared to HD, the cystic fibrosis transmembrane conductance regulator is the most interesting one for the patients included herein, being that its defective production causes the human genetic disease cystic fibrosis by reducing the permeability of Cl- in many tissues, which in turn impairs salt absorption and fluid secretion [41]. This evidence concerns the gene CFTR and Doyne honeycomb retinal dystrophy.