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 for maintaining water and salt balance and also aids mucus production by regulating the movement of water in and out of tissues. Mutations in this protein can dramatically change 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 in the body due to the accumulation of very thick and viscous mucus. This unusually thick mucus can cause breathing problems and bacterial infections that can cause scar tissue and cysts to develop in the lungs. Many people with cystic fibrosis also suffer from digestive problems due to mucus blocking the pancreatic ducts. Blocking these ducts significantly decreases the amount of insulin produced b...