SFTPA1 and cystic fibrosis: Both of the SFTPC SNPs studied, rs4715 and rs1124, are associated with CF through 18 intergenic SNP-SNP interactions with SNPs in SFTPA1, SFTPA2, SFTPC, and SFTPD (X2 is 2.2285–8.4508, p = 0.0487–0.0007) (Table 4).