Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal-recessive disorder caused by variants in the CFTR gene. CFTR normally helps move chloride across epithelial cell membranes; water follows that salt movement. When CFTR function is absent or reduced, secretions lose water and become unusually thick. In the airways, mucus that should be cleared by cilia becomes difficult to move. It plugs smaller bronchi, traps organisms, and creates a cycle of obstruction, infection, inflammation, and structural airway damage. Repeated injury eventually causes bronchiectasis: permanently widened, scarred airways that retain even more secretions. The same problem occurs outside the lungs. Thick pancreatic secretions obstruct pancreatic ducts, reducing digestive enzyme delivery to the intestine. Fat and protein are not absorbed effectively, so the person may have poor weight gain, bulky greasy stools, abdominal discomfort, and deficiencies of fat-soluble vitamins. Salt loss through sweat explains the classic salty skin and increases dehydration risk during fever, hot weather, exercise, vomiting, or diarrhea. CF is not simply “a lung disease with mucus.” Respiratory decline, nutrition, glucose regulation, bowel function, liver disease, fertility, and psychosocial burden can all affect health...