INHERITED THROMBOPHILIAS
The most common inherited thrombophilias are:
●Factor V Leiden (FVL) variant – (See "Factor V Leiden and activated protein C resistance".)
●Prothrombin G20210A variant – (See "Prothrombin G20210A".)
●Protein S deficiency – (See "Protein S deficiency".)
●Protein C deficiency – (See "Protein C deficiency".)
●Antithrombin (AT) deficiency – (See "Antithrombin deficiency".)
The FVL and prothrombin G20210A variants (also called the prothrombin gene mutation [PGM]) together account for 50 to 60 percent of cases of an inherited (primary) hypercoagulable state in White populations. Deficiencies in protein S, protein C, and AT account for most of the remaining cases. Although collectively prevalent in approximately 10 percent of White populations, these disorders appear to be responsible, at least in part, for up to one-half of maternal venous thromboembolism (VTE) [2]. Of note, the prevalence of an inherited thrombophilia in White populations can vary by ethnicity [3].
High-risk types — Individuals with the following inherited thrombophilias are at higher risk for VTE:
●AT deficiency
●FVL homozygote
●Prothrombin G20210A homozygote
●Heterozygosity for both FVL and prothrombin G20210A
Low-risk types — Individuals with the following inherited thrombophilias are at lower risk for VTE:
●FVL heterozygote
●Prothrombin G20210A heterozygote
●Protein C deficiency
●Protein S deficiency