The cystic fibrosis transmembrane conductance regulator (CFTR) is a protein that functions as a channel across cell membranes, moving chloride ions in and out of cells. The movement of chloride ions is important in maintaining water and salt balance and also contributes to mucus production by regulating the movement of water into and out of tissues. Mutations in this protein can dramatically alter the structure and function of chloride ion channels, which can lead to cystic fibrosis and digestive problems as well as congenital bilateral absence of the vas deferens (CBAVD). Cystic fibrosis is a disease that causes damage to many organs of the body due to a buildup of very thick, viscous mucus. This unusually thick mucus can cause breathing problems as well as bacterial infections that can lead to the development of scar tissue and cysts in the lungs. Many people with cystic fibrosis also experience digestive problems due to blockage of the pancreatic ducts with mucus. Blockage of these conduits considerably reduces the amount of insulin produced by...