CFTR and cystic fibrosis: The evolution of 4/8 CF-SPID subjects to CFTR-RD after the third year of life, suggests that the follow-up of CF-SPID must be longer than the two or three years as recently suggested [26] considered that CFTR-RD may develop symptoms later than CF, that most of them are negative to the NBS and that however, the early diagnosis may have a great impact on their final outcome [3,27].