[Diagnosis of cystic fibrosis in adults]

Cystic fibrosis is a genetic recessive disorder caused by mutations in the gene that encodes the CFTR protein. The diagnosis of cystic fibrosis is usually established in early childhood but it is now being made in an increasing number of adults. Many of them present with mild or atypical cystic fibrosis clinical features, mostly lung disease. In addition, some adults with congenital bilateral absence of vas deferens or idiopathic chronic pancreatitis may be assigned a diagnosis of cystic fibrosis. The diagnosis of cystic fibrosis in adults should be based on the presence of one or more characteristic clinical features, a history of cystic fibrosis in a sibling, plus evidence of defective CFTR function as documented by elevated sweat chloride concentrations or abnormal ion transport across the nasal epithelium, or identification of mutations on both CFTR genes.