Overview
Clinical Meaning
Cystic fibrosis is an autosomal recessive disorder caused by pathogenic variants in the CFTR gene.
Cystic fibrosis is an autosomal recessive disorder caused by pathogenic variants in the CFTR gene. Abnormal CFTR chloride and bicarbonate transport changes the water content of secretions. In the airways, mucus becomes thick and difficult to clear, so it obstructs smaller bronchi, impairs mucociliary clearance, and provides a setting for persistent bacterial infection and inflammation. The same transport defect affects several systems. In the pancreas, obstructed ducts reduce delivery of digestive enzymes to the intestine, causing malabsorption, poor weight gain, and bulky, greasy stools. Sweat glands produce unusually salty sweat, which can lead to excessive salt loss during heat, fever, or exercise. CF can also affect the liver and biliary tract and can cause cystic-fibrosis-related diabetes as pancreatic function declines. The respiratory pattern is not simply “a child with a cough.” Chronic airway obstruction and infection may produce persistent cough, wheeze, crackles, exercise intolerance, recurrent sinus disease, and progressive reduction in lung function. An exacerbation is suggested by a meaningful change from the child’s baseline: increased cough or sputum, new dyspnea, fatigue, reduced appetite, a fall in spirometry, or a...