Taken together, in view of the association between gene polymorphism and thrombotic complications in patients with MPN, GPIIIa, XRCC1, FBG, F5, F7, MMP9, HPA5, MTHFR, and SDF-1 polymorphisms are related to vascular events, but not for F2, FAS, FASL, TERT, ACE, and TLR4. The gene discussed is ACE; the disease is myeloproliferative neoplasm.