TY - CHAP M1 - Book, Section TI - Hereditary Thrombophilia A1 - Middeldorp, Saskia A1 - Coppens, Michiel A2 - Kaushansky, Kenneth A2 - Lichtman, Marshall A. A2 - Prchal, Josef T. A2 - Levi, Marcel M. A2 - Press, Oliver W. A2 - Burns, Linda J. A2 - Caligiuri, Michael PY - 2015 T2 - Williams Hematology, 9e AB - SUMMARYThrombophilia refers to laboratory abnormalities that increase the risk of venous thromboembolism (VTE). Over the last several decades numerous factors have been identified. The most prevalent examples of hereditary forms of thrombophilia include the factor V Leiden and prothrombin G20210A mutations; deficiencies of the natural anticoagulants antithrombin, protein C, and protein S; persistently elevated levels of coagulation factor VIII; and mild hyperhomocysteinemia. Taken together, some form of hereditary thrombophilia can be identified in more than 50 percent of patients with VTE who are without obvious reasons for VTE, such as trauma or prolonged stasis. Moreover, hereditary thrombophilia has been associated with arterial cardiovascular disease and obstetric complications such as (recurrent) pregnancy loss and preeclampsia. The high yield of thrombophilia testing has led to widespread testing for these abnormalities in patients. Nevertheless, thrombophilia testing remains a topic of ongoing debate, mostly because of the lack of therapeutic consequences. While hereditary thrombophilia is a clear risk factor for a first VTE, the risk for recurrent episodes is hardly increased compared with nonaffected patients and prolonged anticoagulation is not warranted unless VTE is recurrent. A similar lack of therapeutic consequences applies to patients with arterial cardiovascular disease and women with obstetric complications. Thrombophilia testing in asymptomatic relatives of patients with VTE may be useful in families with antithrombin, protein C, or protein S deficiency, or for siblings of patients who are homozygous for factor V Leiden, and is limited to women who intend to become pregnant or who would like to use oral contraceptives. Careful counseling with knowledge of absolute risks helps patients to making an informed decision in which their own preferences can be taken into account. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1121104701 ER -