Cystic Fibrosis

Abstract

Cystic Fibrosis (CF) is an autosomal recessive disease caused by genetic mutations on chromosome 7. The defective gene results in abnormalities in the production and function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In healthy cells CFTR acts as a chloride channel and a regulator of sodium, chloride and bicarbonate transport. The resulting reduction or absence of CFTR expression in patients with CF results in impaired chloride transport, enhanced sodium absorption, dehydration of airway surface liquid, and deficiency in mucociliary clearance. Viscid secretions develop in the lung as well as in the liver, bowel, and pancreas. These changes result is a multisystem disease that includes progressive bronchiectasis, pancreatic insufficiency, liver disease, and CF-related diabetes. The diagnosis is often suspected in infancy due to bowel complications, such as meconium ileus, recurrent chest infections, or failure to thrive. In the UK there is a national screening programme using the standard heel prick test to measure immunoreactive trypsinogen (IRT). The diagnosis is confirmed by performing sweat tests and CF genetics. Median survival has improved to 40 years due to a multidisciplinary approach with regards to nutrition, airway clearance, and antibiotic therapy. Over recent years there have been several important advances in the development of drugs that directly treat the basic defect.