SFTPB and cystic fibrosis: Table 4 shows that the SFTPA2 gene is associated with CF through 9 intergenic SNP-SNP interactions with SFTPA1 (n = 2), SFTPB (n = 4), and SFTPC (n = 3) (X2 is 2.4172–6.4974, p = 0.0485–0.0038, Figure 1A).