Management of inherited thrombophilia: guide for genetics professionals.

Venous thromboembolism (VTE) is a common source of morbidity and mortality in developed countries. Heritable risk factors for VTE (thrombophilias) can be identified in 30-50% of affected patients. Factor V Leiden, prothrombin 20210G>A, and deficiencies of antithrombin, protein C and protein S increase the risk of a first VTE. However, an individual's thrombotic risk is determined by a complex interplay of genetic, acquired and circumstantial risk factors. At least 50% of VTE events in thrombophilic individuals are provoked by predisposing factors such as immobility, surgery, trauma, cancer, hormonal therapy and pregnancy. Non-modifiable risk factors such as advancing age and family history also increase thrombotic risk. An evidence-based risk factor evaluation is an essential step in VTE prevention. This review will educate genetics professionals about inherited and acquired risk factors for VTE and discuss recommendations for management of asymptomatic individuals with thrombophilia.