For example, SNPs of the SFTPB and the SFTPC by themselves and/or through their interactions were significantly associated with cystic fibrosis (Lin et al., 2018), whereas, SNPs of the SFTPA1 and SFTPA2 and their interactions were associated with an increased HP risk in a Mexican population (Gandhi et al., 2021) and RDS in prematurely born neonates (Amatya et al., 2021). Here, SFTPA2 is linked to hypersensitivity pneumonitis.