NOS3 and necrotizing enterocolitis: Deletion of the eNOS-encoding gene Nos3 results in early-onset and exacerbated NEC (Yazji et al., 2013), and a variant of carbamoyl phosphate synthase 1 (CPS1), a rate-limiting enzyme in arginine biosynthesis, is associated with NEC susceptibility in preterm infants (Moonen et al., 2016).