(See also Overview of Thrombotic Disorders Overview of Thrombotic Disorders In healthy people, homeostatic balance exists between procoagulant (clotting) forces and anticoagulant and fibrinolytic forces. Numerous genetic, acquired, and environmental factors can tip... read more .)
Hyperhomocysteinemia may predispose to arterial thrombosis and venous thromboembolism Deep Venous Thrombosis (DVT) Deep venous thrombosis (DVT) is clotting of blood in a deep vein of an extremity (usually calf or thigh) or the pelvis. DVT is the primary cause of pulmonary embolism. DVT results from conditions... read more 
by injuring vascular endothelial cells. Some experts believe, however, that there is insufficient evidence to link hyperhomocysteinemia to thrombosis definitively.
Plasma homocysteine levels are elevated ≥ 10-fold in homozygous cystathionine beta-synthase deficiency. Milder elevations occur in heterozygous deficiency and in other abnormalities of folate metabolism, including methyltetrahydrofolate dehydrogenase deficiency. The most common causes of hyperhomocysteinemia are acquired
Folate deficiency Folate Deficiency Folate deficiency is common. It may result from inadequate intake, malabsorption, or use of various drugs. Deficiency causes megaloblastic anemia (indistinguishable from that due to vitamin... read more is rare in the Western world due to folate fortification of wheat flour.
The abnormality is established by measuring plasma homocysteine levels in patients with cardiovascular disease or thromboembolism who are suspected of having the disorder.
Treatment of Hyperhomocysteinemia
Dietary supplementation
Plasma homocysteine levels may be normalized by dietary supplementation with folate, vitamin B12, or vitamin B6 alone or in combination; however, it is not been shown that this therapy reduces the risk of arterial or venous thrombosis.
