SFTPA1 and newborn respiratory distress syndrome: A family-based linkage study from North America demonstrated that the SP-A1 6A2 and SP-A2 1A0 haplotypes may increase the susceptibility to RDS in preterm neonates [15]; on the contrary, the SP-A2 1A0 haplotype had a protective effect against RDS in a study of Korean preterm newborns [16].