In summary, when we studied the entire CF cohort, we observed a) Two SNPs (one from SFTPB and the other from SFTPC) to be individually associated with CF; b) Three intragenic interactions (2 of SFTPA1 and one of SFTPB) to associate with CF; c) A total of 34 intergenic interactions of different combinations between the various genes studied, except between SFTPD and SFTPA1 or SFTPA2, to associate with CF; A summary of all the significant intragenic and intergenic interactions is shown in Supplementary Table 3, and Figure 2. This evidence concerns the gene SFTPD and cystic fibrosis.