How does the defect in CFTR contribute to the symptoms of cystic fibrosis?
CFTR (cystic fibrosis transmembrane conductance regulator, ATP-binding cassette (sub-family C, member 7)) is a human gene that provides instructions for making a protein called the cystic fibrosis transmembrane conductance regulator. This protein functions as an ion channel across the cell membrane. Such channels are found in tissues that produce mucus, sweat, saliva, tears and digestive enzymes. Chloride, a component of salt, is transported through the channels in response to cellular signals. The transport of chloride helps control the movement of water (osmosis) in tissues and maintain the fluidity of mucus and other secretions. The CFTR protein also regulates the function of other channels, such as a type of channel that transports sodium across cell membranes. Normal functioning of these channels ensures that organs such as the lungs and pancreas function properly. Cystic fibrosis: More than 1,000 mutations in the CFTR gene have been found but the majority of these have not been a
