Cystic fibrosis (CF) is primarily a disorder of electrolyte transport by epithelial cells in which an anion channel, activated by cyclic adenosine monophosphate (cAMP)-dependent kinase (the cystic fibrosis transmembrane conductance regulator-CFTR) is defective and represents the most common autosomal recessive disease with lethal consequences in Caucasians. This evidence concerns the gene CFTR and cystic fibrosis.