All of the 4 studied SFTPB SNPs, rs7316, rs2077679, rs3024798, and rs1130866, are associated with CF through 18 intergenic SNP-SNP interactions with 3 SNPs in SFTPA1, 4 SNPs in SFTPA2, 4 SNPs in SFTPC, and 7 SNPs in SFTPD (X2 is 2.045–8.3123, p = 0.0398–0.0043) (Table 4). This evidence concerns the gene SFTPD and cystic fibrosis.