Therefore, PTH-rP and PTH-R1 are more expressed in placentas from GDM patients with a phenotype characterized by increased insulin resistance due to metabolic syndrome, increased fasting glycemia, and normal glycemia after fuel load, rather than in placentas from GDM patients with impaired insulin secretion, which usually present normal fasting glycemia and abnormal increased glycemia after fuel load. The gene discussed is PTH1R; the disease is metabolic syndrome.