Cystic fibrosis is a life-threatening genetic disease that causes mucus to build up and clog some of the organs in the body, particularly the lungs and pancreas. When mucus clogs the lungs, it can make breathing very difficult. The thick mucus also causes bacteria (or germs) to get stuck in the airways, which causes inflammation (or swelling) and infections that lead to lung damage.
Mucus also can block the digestive tract and pancreas. The mucus stops digestive enzymes from getting to the intestines. The body needs these enzymes to break down food, which provides important nutrients to help people grow and stay healthy. People with cystic fibrosis often need to replace these enzymes with medicine they take with their meals and snacks, which helps them digest food and get proper nutrition.
Normally, the healthy CF gene makes a protein — known as CFTR (Cystic Fibrosis conductance Transmembrane Regulator) — that is found in the cells that line various organs, like the lungs and the pancreas. This protein controls the movement of electrically charged particles, like chloride and sodium (components of salt) in and out of these cells.
When the protein is defective, as in cystic fibrosis, the salt balance in the body is disturbed. Because there is too little salt and water on the outside of the cells, the thin layer of mucus that helps keep the lungs free of germs becomes very thick and difficult to move. And because it is so hard to cough out, this mucus clogs the airways and leads to infections that damage the lungs