PHGDH and fetal growth restriction: In these pathways, the gene expression levels involved in de novo serine synthesis (PHGDH, PSAT1, and PSPH), and the glycine cleavage system (GNMT, ALAS2, DMGDH, BHMT, GATM, GCAT, and AGXT2), as well as dimethylglycine (DMG), were dysregulated in the livers of IUGR piglets.