Five marker genes were upregulated in PD patients’ than in healthy individuals’ endothelial cells, including ANGPT2, APOD, HSP90AA1, HSPA1A, and PDE1C. Their upregulation was confirmed in 18 PD patients’ compared with 18 healthy individuals’ blood specimens through RT-qPCR and Western blotting. The gene discussed is PDE1C; the disease is Parkinson disease.