Several polymorphisms in genes of the hemostasis system are of particular interest, such as the mutation of factor V, factor II, mutation of the gene for the PAI-1 plasminogen activator inhibitor of the fibrinogen β-chain [11], polymorphism of the thrombocytic GP IIIa fibrinogen receptor, integrin α2, platelet glycoprotein 1B mutation [12], polymorphism of methylene-tetrahydrofolate reductase and methionine synthase reductase, which are associated with the homocysteine metabolic disorder. The gene discussed is MTRR; the disease is Other metabolic disease.