CFTR and cystic fibrosis: Our data indicate that: (i) the number of CF-SPID revealed at the NBS is about two-fold the number of patients with CF; (ii) 2 of the 80 (2.5%) subjects with CF-SPID evolved to CF, while eight (10%) evolved to CFTR-RD so far; (iii) half of patients evolved to CFTR-RD were diagnosed > 3 years; (iv) no data at the NBS or during the follow-up was predictive of the evolution from CF-SPID to CF or to CFTR-RD.