It should be noted, however, that our study cohort consisted solely of late-preterm infants, a population that has not been studied previously [13, 15, 16, 18]; it has been suggested that the complex cross-talk between structural lung maturity and SP-A genetic variants may present gestational-age variations that influence the development of RDS in preterm neonates [14]. This evidence concerns the gene SFTPA2 and newborn respiratory distress syndrome.