CFTR and cystic fibrosis: Within group B, 32 subjects were revealed as compound heterozygous for two CFTR mutations; of these, eight had a normal ST and were free of CF-related symptoms, while among the 24 subjects revealed as CFTR-RD, all had an intermediate ST (between 36 and 56 mmol/L) and mono-organ involvement, i.e., bronchiectasis, four cases; congenital bilateral absence of vas deferens (CBAVD), three cases; recurrent pancreatitis, three cases; chronic pancreatitis, six cases; hypochloremic metabolic alkalosis, four cases; nasal polyposis requiring surgery, four cases.