Controversies in the management of pulmonary disease due to cystic fibrosis.

CHEST I 95 I 6 I JUNE, 1989 1319 C ystic fibrosis is a systemic disorder transmitted by autosomal recessive genetics which is still characterized as the most common fatal genetic disease in whites. Approximately 5 percent of the US white population are carriers of the CF gene. Carriers of the CF mutation do not manifest symptoms, a heterozygote advantage has not been demonstrated, and there is at present no carrier test that can be applied to the general population. The basic biochemical abnormality in CF is not known, although rapid progress is being made toward that end. Molecular biologists using recombinant DNA techniques have located the CF gene on a small portion ofthe long arm of chromosome 7, providing a major step toward isolating the gene itself and finally understanding the biochemical pathways involved in the clinical manifestations of CF. All fields of medicine may be touched by this disease, and it is possible for the astute physician to find adult patients with CF while evaluating chronic sinusitis, asthma, pancreatic insufficiency, sprue-like symptoms, azoospermia, or cirrhosis and portal hypertension. Similarly, there is great variability in the clinical course of this disease, and deterioration does not occur at the same rate in all patients. Although CF is a systemic disorder, it is the pulmonary disease, recurrent pulmonary bacterial infections superimposed on chronic colonization of the airways and resultant inflammation leading to destructive disease of the airways (bronchiectasis), which causes most of the morbidity. Ninety percent of CF patients die of respiratory failure. Despite the promise that molecular biology holds for the ultimate therapy for CF, standard care for