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Venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), occurs secondary to a number of hereditary and acquired disorders of hemostasis. A recently recognized polymorphism in Factor V (FV) gene H1299R (also named HR2) has been reported to be a possible risk factor for the development of VTE. The aim of this study is to evaluate the role of HR2 polymorphism in VTE in a group of Lebanese patients. Seventy-three VTE patients and 125 healthy subjects were examined for HR2. The average ages for the patients and controls were 45.0+/-19.1 years and 35.4+/-18.6 years, respectively. Sixty patients (82.2%) had DVT, eight patients (11%) had PE, and five patients (6.8%) had both. There was significant association between FV Leiden and VTE (p<0.001). HR2 haplotype had a prevalence of 16.4% in patients. VTE patients with normal FV were 2.7 times more likely to have the HR2 haplotype as compared to controls with normal FV (p=0.036, 95% CI=1.04-7.06). We conclude that the FV HR2 haplotype significantly affects the risk of VTE in subjects with normal FV. This finding entails that screening for the HR2 haplotype should be done in VTE patients with normal FV Leiden results.

Cerebral venous and sinus thrombosis (CVST) is a multifaceted disorder. The frequency of inherited and acquired thrombophilia among 16 CVST patients was evaluated. The mean age of the patients was 22.9 years. Five out of the 16 CVST patients (31.2%) showed the G1691A mutation of factor V. The frequency of the C677T methylenetetrahydrofolate reductase (MTHFR) genotype was 50% (8/16) in patients (2 of them were homozygous). Four of the patients (25%) had both factor V Leiden and MTHFR mutation. Three of the patients had positive antiphospholipid antibodies. At the time of CVST, 2 female patients were taking oral contraceptive pills. Four patients were known to have malignancies. Despite the limitation of the sample size, we identified an inherited coagulopathy at high rate in our patients. Combined inherited thrombophilia was also present in 25% of patients. This finding supports the impression of a multifactorial process leading to CVST in Lebanese patients.

Aims: A recently identified polymorphism in factor V gene (His1299Arg; also named HR2) has been reported to be a possible risk factor for the development of venous thromboembolism (VTE), with a high prevalence of 9.5-15.2% in patients of different ethnic groups in different parts of the world. The aim of this study is to assess the prevalence of HR2 haplotype in Lebanon., Methods: We randomly selected 125 samples from unrelated donors logged into our HLA registry; these represent healthy Lebanese individuals originating from different provinces and religious communities of the country. Their DNA was extracted using the Pel-Freez extraction kit and stored at -80 degrees C for later use. The CVD StripAssay was used for PCR and reverse hybridisation. It screens for several gene mutations including factor V H1299R., Results: A total of 125 controls were studied: 72 males and 53 females with a median age 42 years. Thirteen (10.4%) had the HR2 haplotype; 11 (8.8%) were heterozygous (R1/R2), and two (1.6%) were homozygous (R2/R2), with an allelic frequency of 0.06., Conclusions: Our study is the first report from Lebanon that describes the prevalence of HR2 haplotype and the frequency of its alleles. We are reporting a high prevalence of the HR2 in our population (10.4%). The hypothesis that A4070G polymorphism might contribute to the expression of a thrombotic phenotype deserves to be tested in our population through larger studies.