Cystic fibrosis (CF) is a multisystem disease affecting epithelia of the respiratory tract, exocrine pancreas, intestine, hepatobiliary system, and exocrine sweat glands. Morbidities include recurrent sinusitis and bronchitis, progressive obstructive pulmonary disease with bronchiectasis, exocrine pancreatic deficiency and malnutrition, pancreatitis, gastrointestinal manifestations (meconium ileus, rectal prolapse, distal intestinal obstructive syndrome), liver disease, diabetes, male infertility due to hypoplasia or aplasia of the vas deferens, and reduced fertility or infertility in some women. Pulmonary disease is the major cause of morbidity and mortality in CF.

Patients with bronchiectasis with or without elevated sweat chloride-2 (BESC2) have bronchiectasis and chronic bronchitis of varying severity. Pancreatic insufficiency may be present (Azad et al., 2009). For discussion of genetic heterogeneity in bronchiectasis with or without elevated sweat chloride, see BESC1 (211400).