Table 1.

Types of inherited thrombophilia and their prevalence^17,19-21

Proposed category system	Type of syndrome	% of general population	% of those with thrombosis
1. Qualitative and quantitative defects of those factors inhibiting clotting	Antithrombin deficiency	0.2	1-3
	Protein C deficiency	0.2-0.4	3-5
	Protein S deficiency	0.03-0.1	1-5
	Heparin cofactor II deficiency	~ 1	~ 1
	Tissue factor pathway inhibitor deficiency	a	a
	Thrombomodulin deficiency	a	a
2. Qualitative and quantitative defects of those factors promoting clotting	Activated protein C resistance and factor V Leiden	5	10-50
	Prothrombin gene mutation	2-5	6-18
	Dysfibrinogenemia and hyperfibrinogenemia	< 1	< 1
	Elevated levels of clotting factors VIII	11	25
	Elevated levels of clotting factors VII, IX, XI, and XII	a	a
3. Hyperhomocysteinemia		5	10
4. Defects of the fibrinolytic system	Plasminogen	a	a
	Tissue plasminogen activator	a	a
	Thrombin-activatable fibrinolysis	a	a
	Factor XIII	a	a
	Lipoprotein (a)	a	a
5. Altered platelet function	Platelet glycoprotein GPIb-IX	a	a
	GPIa-IIa	a	a
	GPIIb-IIIa	a	a

Modified table republished with permission from Informa Healthcare, Copyright 2006. Franchini M, Veneri D, Salvagno GL, Manzato F, Lippi G. Inherited thrombophilia. Crit Rev Clin Lab Sci 2006;43:249-90.

^aPercentages unknown or not reported.