SFTPA2 and newborn respiratory distress syndrome: Specific SP-A haplotypes have been shown to predispose to RDS while others have a protective effect, albeit with significant ethnical and racial differences [13–16]; an association between RDS and SP-B polymorphisms, such as the SP-B Ile131Thr polymorphism and the Δi4 length variation, has also been suggested [14,17–19].