Nonclassic cystic fibrosis and CFTR-related diseases

Purpose of review: To review the spectrum of disease caused by mutations in the cystic fibrosis (CF) gene. Recent findings: The growing recognition of "atypical" cases of cystic fibrosis presenting in adolescence or adulthood and manifested by disease in only one or two organ systems, along with CF diagnostic criteria based not only on sweat chloride values but genetic screening and nasal ion transport measurements, have made the diagnosis of CF less straightforward for many clinicians. Summary: This review seeks to clarify the key diagnostic criteria for CF and uses the Cystic Fibrosis Foundation's Consensus Diagnostic Guidelines and recent publications to discuss the characteristics of classic CF, nonclassic CF, and CFTR-related diseases.