Prothrombotic mutations, family history and the risk of thrombosis in postmenopausal women: implications for hormone replacement therapy.

OBJECTIVE: Hormone replacement therapy (HRT) is acknowledged as the gold standard for the alleviation of climacteric vasomotor symptoms. Prothrombotic genetic variants have been suggested to increase thrombotic risk among HRT users. The aim of the study was to determine whether a positive family history may identify a genetic predisposition for thrombosis in women before prescribing HRT. METHODS: From January 2005 to May 2009, we consecutively enrolled 145 asymptomatic women (mean age 51.2 ±â€Š5.4 years) without previous episodes of venous and/or arterial thrombosis referred to our Genetics Research Unit before starting HRT. A detailed family history was reconstructed and we identified 48 women (33.1%) with a positive family history, defined as venous thromboembolism and/or stroke or heart attack, in first-degree relatives before 60 years for men and 65 years for women. A group of 121 women (mean age 54.0 ±â€Š9.1 years) with an episode of venous and/or arterial thrombosis was also included. Genetic screening for factor V Leiden, prothrombin G20210A and methylenetetrahydrofolate reductase C677T polymorphisms was performed. RESULTS: The frequency of factor V Leiden or prothrombin G20210A mutations was significantly higher both in asymptomatic women with a positive family history (16.7% vs. 2.1%, p = 0.001) and in patients with thrombosis (12.4% vs. 2.1%; p = 0.005) compared with asymptomatic women without a family history. Multivariate regression analysis showed a synergic effect between the presence of one prothrombotic mutation and family history on the risk of thrombosis (odds ratio 3.7, 95% confidence interval 1.9-7.2). CONCLUSIONS: A positive family history of thrombosis is a sensitive indicator for selected genetic testing in high-risk women before starting HRT.