[From gene to disease; from defective chloride ion transport to cystic fibrosis].

Cystic fibrosis is an autosomal recessive disorder affecting the lungs, pancreas, intestines, sweat ducts and liver, due to an abnormal salt transport across the apical border of epithelial cells. Mutations in the CF underlying gene, the cystic fibrosis transmembrane conductance regulator (CFTR) gene, result in most cell types in an misprocessing so that little of the protein reaches the membranes. In case of clinical suspicion and/or doubtful sweat test results, mutation analysis can support the diagnosis of CF. Also carrier detection is offered.