The haplotypes “CC” of the SFTPA2 (rs1059046 x rs17886395), OR = 0.07 (0.02–0.26) and “AA” of the SFTPA1 (rs1136451 x rs1059057), OR = 0.30 (0.12–0.78), exhibited a dominant effect on decreased HP risk. The gene discussed is SFTPA2; the disease is hypersensitivity pneumonitis.