CPS1 and necrotizing enterocolitis: Although the present study was not powered to detect differences in amino acid levels or CPS1 genotype between infants with and without NEC, we observed that the mean L-arginine level of NEC infants showed a non-significant trend to lower values (median 29 μmol/l, interquartile range 16–44 vs. median 40 μmol/l, interquartile range 23–57 in non-NEC group).