These cases are generally characterized by a later onset of symptoms such as pancreatitis, [13] disseminated bronchiectasis, congenital bilateral absence of vas deferens (CBAVD) associated to normal or borderline sweat chloride concentrations (30–59 mmol/L for infants less than 6 months of age, 40–59 mmol/L for older individuals) and two CF mutations with a different degree of CFTR protein dysfunction [14]. This evidence concerns the gene CFTR and cystic fibrosis.