This document discusses genetic and acquired risk factors for thrombosis. Common genetic risk factors include mutations in factor V Leiden, prothrombin, and MTHFR genes. Acquired risk factors with high thrombosis risk are tissue injury, cancer, prosthetic heart valves, disseminated intravascular coagulation, heparin-induced thrombocytopenia, and antiphospholipid antibody syndrome. Additional acquired factors with lower risk include cardiomyopathy, nephrotic syndrome, pregnancy, oral contraceptive use, sickle cell anemia, and smoking.

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Prolonged bedrest or
immobilization
Atrial fibrillation
Tissue injury (surgery,
fracture, burn)
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hypertension
ATS
IM
vasculitis
turbulent blood flow
bacterial endotoxins
radiation injury
metabolic abnormalities such
as homocystinemia
hypercholesterolemia
toxins absorbed from
cigarette smoke

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primary (genetic)
Common
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Rare
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Fibrinolysis defects
Homozygous homocystinuria (deficiency of cystathione β-synthetase)
secondary (acquired)
High Risk for Thrombosis
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Antithrombin III deficiency
Protein C deficiency
Protein S deficiency
Very Rare
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Factor V mutation (G1691A mutation; factor V Leiden)
Prothrombin mutation (G20210A variant)
5,10-Methylenetetrahydrofolate reductase (homozygous C677T mutation)
Increased levels of factors VIII, IX, XI, or fibrinogen
Tissue injury (surgery, fracture, burn)
Cancer
Prosthetic cardiac valves
Disseminated intravascular coagulation
Heparin-induced thrombocytopenia
Antiphospholipid antibody syndrome
Lower Risk for Thrombosis
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Cardiomyopathy
Nephrotic syndrome
Hyperestrogenic states (pregnancy and postpartum)
Oral contraceptive use
Sickle cell anemia
Smoking