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ALL / Haematology
Thrombophilia: causes
Thrombophilia: causes
Inherited
Gain of function polymorphisms
- factor V Leiden (activated protein C resistance): most common cause of thrombophilia
- prothrombin gene mutation: second most common cause
Deficiencies of naturally occurring anticoagulants
- antithrombin III deficiency
- protein C deficiency
- protein S deficiency
The table below shows the prevalence and relative risk of venous thromboembolism (VTE) of the different inherited thrombophilias:
| Condition | Prevalence | Relative risk of VTE |
|---|---|---|
| Factor V Leiden (heterozygous) | 5% | 4 |
| Factor V Leiden (homozygous) | 0.05% | 10 |
| Prothrombin gene mutation (heterozygous) | 1.5% | 3 |
| Protein C deficiency | 0.3% | 10 |
| Protein S deficiency | 0.1% | 5-10 |
| Antithrombin III deficiency | 0.02% | 10-20 |
Acquired
Antiphospholipid syndrome
Drugs
- the combined oral contraceptive pill
+PassMedicine Notes
Inherited
Gain of function polymorphisms- factor V Leiden (activated protein C resistance): most common cause of thrombophilia
- prothrombin gene mutation: second most common cause
- antithrombin III deficiency
- protein C deficiency
- protein S deficiency
The table below shows the prevalence and relative risk of venous thromboembolism (VTE) of the different inherited thrombophilias:
Condition _ Prevalence _ Relative risk of VTE| Factor V Leiden (heterozygous) _ 5% _ 4| Factor V Leiden (homozygous) _0.05% _ 10| Prothrombin gene mutation (heterozygous) _ 1.5% _ 3| Protein C deficiency _ 0.3% _ 10| Protein S deficiency _ 0.1% _ 5-10| Antithrombin III deficiency_ 0.02% _ 10-20|Acquired
Antiphospholipid syndrome
Drugs- the combined oral contraceptive pill
