In contrast, serine metabolism appears to be downregulated, since transcripts of genes coding for D-3-phosphoglycerate dehydrogenase (PGDH, EHI_060860), methionine γ-lyase 1 (MGL1, EHI_144610), and phosphoserine aminotransferase (PSAT, EHI_026360) were downregulated in iron deficiency. The gene discussed is PHGDH; the disease is nutritional disorder.