In addition, in a subsequent case–control study, preterm infants with RDS (n = 31) had significantly higher plasma levels of oxidative stress markers (malondialdehyde (MDA) and hydrogen peroxide (H2O2)) and reduced activity of antioxidant enzymes (catalase (CAT) and superoxide dismutase (SOD)) when compared with healthy preterm newborns (n = 36) [32]. This evidence concerns the gene CAT and newborn respiratory distress syndrome.