CFTR and cystic fibrosis: The clinical diagnosis of CF was established based on consensus clinical criteria [7], [8], namely: 1) presence of one or more characteristic phenotypic features (chronic sinopulmonary disease; gastrointestinal/nutritional abnormalities; obstructive azoospermia or salt-loss syndrome) and 2) evidence of a CFTR abnormality (increased sweat [Cl−] (>60 mEq/L) and/or detection of two CF-disease causing mutations).