Exon 2 was replaced with one in which a C to G mutation results in the amino acid substitution of arginine with glycine at position 242 (p.R242G on precursor or p.R227G on mature peptide). A loxP site was inserted into intron 1 and a loxP site flanked neomycin resistance gene cassette into intron 2. The mutation mimics a human SNP (p.R231G on precursor or p.R213G on mature peptide) that is associated with susceptibility to cardiovascular and lung disease. (J:212043, J:285340)