The risk of venous thromboembolism in oral contraceptive users: the role of genetic factors-a prospective cohort study of 240,000 women in the UK Biobank.

BACKGROUND: More than 150 million women worldwide use oral contraceptives. Women with inherited thrombophilia and carriers of certain thrombophilia gene variants, such as factor V Leiden and the prothrombin, are at an increased risk for venous thromboembolism, especially when combined with oral contraceptive use. Venous thromboembolism is a complex disorder involving many genetic risk factors, and recently, polygenic risk scores have been proposed to capture a significant proportion of the genetic risk of venous thromboembolism. OBJECTIVE: The aim of this study was to estimate the risk for developing venous thromboembolism when initiating oral contraceptive use (first 2 years) and during continued use among women with a high genetic liability. STUDY DESIGN: We used a prospective study design in which 244,420 participants from the UK Biobank were followed from birth. The effect of oral contraceptive use during the first 2 years and in the remaining years of oral contraceptive use on the risk of developing venous thromboembolism was estimated using a Cox regression with a time-dependent exposure variable. Women were stratified according to their polygenic risk scores and whether they were carriers of factor V Leiden and/or prothrombin variants. RESULTS: When genetic risk was not considered, an increased risk for venous thromboembolism was observed during the first 2 years of oral contraceptive use (hazard ratio, 3.09; 95% confidence interval, 3.00-3.20) but not during continued use (hazard ratio, 0.92; 95% confidence interval, 0.80-1.05). However, when genetic risk was considered, women in the highest polygenic risk score category had a more pronounced risk of developing a venous thromboembolism during the first 2 years of oral contraceptive use (hazard ratio, 6.35; 95% confidence interval, 4.98-8.09), and a high risk was also observed among factor V Leiden (hazard ratio, 5.73; 95% confidence interval, 5.31-6.17) and prothrombin variant carriers (hazard ratio, 5.23; 95% confidence interval, 4.67 - 5.87). A high polygenic risk score in combination with being a factor V Leiden and prothrombin variant carrier conferred the highest risk for developing a venous thromboembolism during the first 2 years of oral contraceptive use (hazard ratio, 14.8; 95% confidence interval, 9.28-23.6). Women with a high genetic liability also had an increased risk during continued use but it was less pronounced, and the highest risk was conferred to carriers of both factor V Leiden and the prothrombin variant (hazard ratio, 4.93; 95% confidence interval, 3.16-7.7). CONCLUSION: Evaluating polygenic risk can identify additional venous thromboembolism risk that is not captured in the commonly investigated genes for inherited thrombophilia. Our results indicate that oral contraceptive use is associated with an increased risk for developing a venous thromboembolism, particularly among women with a high genetic predisposition, and that oral contraceptive use dramatically increases the risk thereof short after initiation of use, which decreases with continued use. This suggests that the polygenic risk score could be used to identify women who are at high risk for developing a venous thromboembolism and advise them on alternative methods of contraception.

Pregnancy complications in G20210A mutation carriers associated with high prothrombin activity.

OBJECTIVE: To study the association between high activity of Factor II (prothrombin) in blood plasma with G20210A mutation and the development of great obstetrical syndromes. MATERIAL AND METHODS: A prospective clinical cohort study was conducted on 290 pregnant women (average age 31.7 ± 4.7 years old). The main group was made up of 140 G20210A patients, while the control group comprised 150 women with the wild G20210G type. The aim was to evaluate the activity of Factor II in the venous blood plasma during the stages of pregnancy with regard to trophoblast invasion waves. As per results, association analysis of Factor II activity value and gestational complications was carried out. RESULTS: In the control group, the median (Me) of Factor II activity ranged from 108% (preconception period) to 144% (pregnancy) [95% CI 130-150]. In patients with the GA type, the value was significantly higher in related periods, ranging from 149 to 181% [95% CI 142-195], p < 0.0001. With Factor II activity ranging from 148.5 to 180.6%, pregnancies in the main group had no complications. Higher levels of Factor II activity were associated with the development of early and/or severe preeclampsia (PE) and fetal growth retardation (FGR). CONCLUSION: The data obtained regarding Factor II activity in blood plasma, juxtaposed with the development of great obstetrical syndromes, allow to assume that manifestation of G20210A in early and/or severe PE and FGR is associated with this coagulation factor's level of activity. Threshold value of the Factor II activity with G20210A mutation, allowing to predict the development of PE, comprised 171.0% at the preconception stage (AUC - 0.86; p < 0.0001) and within 7-8 weeks of gestation it was 181.3% (AUC - 0.84; p < 0.0001).

MTHFR (C677T, A1298C), FV Leiden polymorphisms, and the prothrombin G20210A mutation in arterial ischemic stroke among young tunisian adults.

Arterial ischemic stroke (AIS) in young adults is less common in older adults, but the underlying pathogenesis and risk factors are more multi-faceted. The role of inherited thrombophilia such as 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism, (C677T and A1298C), factor V of Leiden (FVL) polymorphism, and the prothrombin G20210A mutations remains unclear. This study aims to evaluate the role of prothrombin genetic factor in AIS among young adults in Tunisia and to assess the synergistic effect between thrombogenic mutations in the pathogenesis of AIS. In this case-control study, blood samples were collected from patients and healthy controls, all matched for age and gender. The difference between them is evaluated by using the chi-square test. The odds ratio (OR) was carried out to evaluate the associations between each polymorphism and AIS risk using a binary logistic regression model. Values were considered statistically significant when p < 0.05. Patients carrying simultaneously the MTHFR polymorphisms (677T and 1298C) have a higher risk to develop AIS compared to controls. The heterozygous variants FVL increased the risk of AIS only when it is associated with MTHFR C677T or MTHFR A1298C polymorphisms. In conclusion, our study confirmed the involvement of MTHFR polymorphisms as AIS's important risk factors. The existence of FVL polymorphism or prothrombin G20210A mutation alone doesn't correlate with the occurrence of stroke. We assume that the presence of both MTHFR and FVL polymorphisms has a synergistic effect and increased the risk of the AIS.

Risk Factors of Venous Thromboembolism in Sudanese Pregnant Women.

Venous thromboembolism (VTE) is one of the major causes of pregnancy-related mortality and morbidity. This study aimed to determine the frequency of factor V Leiden (FVL) and prothrombin G20210A polymorphisms and measure the plasma levels of protein C (PC), protein S (PS) and antithrombin (AT) in pregnant women with VTE and healthy pregnant women. This prospective case-control study determined the frequencies of FVL G1691A and prothrombin G20210A polymorphisms and measured the plasma levels of PC, PS and AT in 198 pregnant women with VTE and 198 healthy pregnant women. Allele-specific polymerase chain reaction (ASPCR) was used to detect the FVL G1691A polymorphisms and prothrombin G20210A gene mutations. The FVL G1691A polymorphism and prothrombin G20210A gene mutations were detected only in pregnant women with VTE, with frequencies of 4.0 and 0.5%, respectively. The highest frequency of FVL G1691A polymorphism was observed in patients with deep vein thrombosis (DVT) and positively associated with contraceptive use and termination. Pregnant women with VTE had significantly lower levels of PC, PS and AT than those of controls. In conclusion, among the VTE cases, FVL G1691A polymorphism and PC, PS and AT deficiencies were the most common findings in patients presenting with DVT. Antithrombin deficiency was more common than PC and PS deficiencies. Contraceptive use, high body mass index (BMI) and termination correlated strongly with FVL G1691A polymorphism and PC and PS deficiencies in patients with VTE.

Interaction of thrombophilic SNPs in patients with unexplained infertility-multifactor dimensionality reduction (MDR) model analysis.

PURPOSE: Our aim was to evaluate the frequency and SNP-SNP interactions between factor V Leiden (FVL) G1691A, prothrombin G20210A mutation, and C677T MTHFR and PAI-1 4G/5G gene polymorphisms in female IVF patients with unexplained infertility (UI) by using a multifactor dimensionality reduction (MDR) model analysis. METHODS: A total of 225 subjects were enrolled in the study. There were 105 females in UI group and 120 healthy controls. Designated SNPs were determined by using allele-specific PCR methods. The difference in thrombophilia prevalence was assessed by a chi-square test and logistic regression analysis. Four-locus SNP interaction model was tested using the MDR approach. A ten-fold cross-validation consistency (CVC) and permutation testing were performed. RESULTS: There was a significant difference of MTHFR C677T polymorphism frequency between the groups. Significantly less UI patients had MTHFR CC genotype (p = 0.005), while the risk allele T was more frequent (OR = 1.83, p = 0.0018). Logistic regression determined a significant association only for MTHFR C677T in our patients (TT genotype OR = 2.99). The MDR analysis confirmed the significance of a single-locus model for MTHFR C677T polymorphism (p = 0.015; OR = 2.93). However, the best, significant predictive model was the two-locus model comprising MTHFR C677T and FVL (CVC = 10/10, testing accuracy = 60.95%, p = 0.013; OR = 3.02). CONCLUSION: The MTHFR C677T polymorphism was significantly associated with UI, with minor allele T being more frequent. Additionally, there was a significantly increased presence of MTHFR C677T with FVL mutation in these patients. Therefore, MTHFR and its interaction with FVL should be recognized as contributing factors in the pathogenesis of infertility.

Searching for genetic variants associated with thrombophilia.

Thrombotic states are inherited or acquired predisposition for thrombosis in the human vascular system. Nowadays Leiden mutation and mutation in prothrombin G20210A contributing to congenital thrombophilia are routinely tested. These mutations have a high prevalence in the population. Congenital deficiencies of protein S, protein C and antithrombin III are rare thrombophilia with lower population frequency, but higher risk of thromboembolic event. The genetic causes are mutations in the genes, which encode these proteins. The choice of proper molecular genetic testing depends on the difference in the detection of well-known single nucleotide polymorphism or unknown/rare variant. For the detection of causative variant FV Leiden and prothrombin G20210A are mostly used PCR-RFLP, reverse Strip Assay®, allele-specific PCR, TaqMan real-time PCR and SNaPshot®. Precise patient selection should precede the genetic testing of rare variants in anticoagulant proteins. It is appropriate to use methodology of massive parallel sequencing supplemented by a methodology for the detection of larger gene rearrangements - MLPA. We are successfully employing this approach in our institute. This methodology is faster with larger analytic capacity compared to commonly used direct sequencing by Sanger method.

Factor V Leiden is associated with increased sperm count.

STUDY QUESTION: Is the thrombophilia mutation factor V Leiden (FVL) associated with an increased total sperm count? SUMMARY ANSWER: Carriers of FVL have a higher total sperm count than non-FVL-carriers, which could not be explained by genetic linkage or by observations in a FVL-mouse model. WHAT IS KNOWN ALREADY: FVL has a high prevalence in Caucasians despite detrimental health effects. Carriers have been shown to have higher fecundity, which might partly explain this evolutionary paradox. STUDY DESIGN, SIZE, DURATION: We determined FVL status in two cohorts (Dutch, n = 627; Danish, n = 854) of consecutively included men without known causes for spermatogenic failure, and performed an individual patient data meta-analysis of these two cohorts together with one previously published (Dutch, n = 908) cohort. We explored possible biological underpinnings for the relation between sperm count and FVL, by use of a FVL-mouse model and investigations of genetic linkage. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were male partners of subfertile couples (two Dutch cohorts) and young men from the general population (Danish cohort): FVL carrier rate was 4.0%, 4.6% and 7.3%, respectively. There were differences in smoking, abstinence time and age between the cohorts. We corrected for these in the primary analysis, which consisted of a mixed linear effects model, also incorporating unobjectified population differences. In public haplotype data from subjects of European descent, we explored linkage disequilibrium of FVL with all known single nucleotide polymorphisms in a 1.5 MB region around the F5 gene with an R2 cutoff of 0.8. We sequenced exons of four candidate genes hypothesized to be linked to FVL in a subgroup of FVL carriers with extreme sperm count values. The animal studies consisted of never mated 15-18-week-old C57BL/J6 mice heterozygous and homozygous for FVL and wild-type mice. We compared spermatogenesis parameters (normalized internal genitalia weights, epididymis sperm content and sperm motility) between FVL and wild-type mice. MAIN RESULTS AND THE ROLE OF CHANCE: Human FVL carriers have a higher total sperm count than non-carriers, with an adjusted mean difference of 31 × 106 (95%CI 0.2-61.7; P = 0.048). Mice with the FVL mutation do not have increased spermatogenesis as compared to wildtype mice. None of the studied polymorphisms was in linkage disequilibrium, either in the public databases or in a subgroup of FVL carriers with extremely high sperm counts. LIMITATIONS, REASONS FOR CAUTION: The difference in total sperm count would benefit from confirmation in other cohorts. The finding of higher count in carriers was consistent however, with no heterogeneity between the cohorts. The lack of effect of murine FVL might suggest there is no direct causality. The exploratory efforts on genetic linkage do not rule out that the association is a reflection of FVL co-inheritance with a non-studied causative polymorphism. WIDER IMPLICATIONS OF THE FINDINGS: A high sperm count in FVL-carrying males contributes to understanding the high prevalence of this otherwise disadvantageous mutation. The findings might provide directions for future research on male fertility. STUDY FUNDING/COMPETING INTEREST(S): No conflicts of interest. Research was conducted with funding from the Netherlands Organisation for Scientific Research (NWO, VIDI innovative research grant 016.126.364 awarded to S. Middeldorp). The Danish cohort was supported by the Innovation Fund Denmark (InnovationsFonden, grant no. 14-2013-4), The Danish Ministry of Health and the Danish Environmental Protection Agency. TRIAL REGISTRATION NUMBER: Not applicable.

Prothrombin G20210A mutation and lower extremity peripheral arterial disease: a systematic review and meta-analysis.

OBJECTIVE/BACKGROUND: Despite being an important risk factor for venous thromboembolism, the role of the prothrombin G20210A mutation in patients with arterial disease remains unclear. The aim of this review was to evaluate the association of prothrombin G20210A and lower extremity peripheral arterial disease (PAD). METHODS: This was a systematic review and meta-analysis of case-control studies. A systematic review of electronic databases, including MEDLINE and Embase, was conducted to assess the prevalence of prothrombin G20210A in patients with lower extremity PAD. The main outcome was the prevalence of prothrombin G20210A in patients with lower extremity PAD. The random effects model odds ratio (OR) was used as the primary outcome measure. RESULTS: The initial electronic search identified 168 relevant abstracts of which five studies evaluating 1,524 cases of PAD and 1,553 controls were included. Prothrombin G20210A was found in 70 of 1,524 patients with lower extremity PAD and 44 of 1,553 of the controls (random effects OR 1.68, 95% confidence interval [CI] 0.8-3.2). In those with critical limb ischemia (CLI), the prevalence of prothrombin G20210A was 23 of 302 compared with 31 of 1,253 of the controls (OR 3.2, 95% CI 1.6-6.1). CONCLUSION: Despite finding no significant association between lower extremity PAD and prothrombin G20210A, the meta-analysis suggests that the prevalence of prothrombin G20210A is significantly elevated in those with atherosclerotic occlusive disease of the lower extremities presenting with CLI. Well-designed prospective cohort studies evaluating the role of prothrombin G20210A as a predictor of disease progression or adverse vascular events are highly needed.

Isolated cortical vein thrombosis associated with prothrombin gene mutation.

Isolated cortical vein thrombosis (ICVT) accounts for less than 1% of strokes. We report a 47-year-old female patient who had a frontal hemorrhage with headache associated with contralateral hemiparesis and hemisensory deficit on presentation. This hemorrhagic stroke was localized in a nonarterial territory, and it was caused by ipsilateral and isolated thrombosis of the vein of Labbe found on catheter angiogram that demonstrated a filling defect of the vein of Labbe at its connection with the transverse sinus. There were no filling defects in the superficial middle cerebral veins. Our patient had a family history of cardiovascular disease, stroke, and factor V Leiden mutation and cigarette smoking as stroke risk factors. Complete prothrombotic state laboratory workup revealed a heterozygous prothrombin G20210 A gene mutation. The patient's hospital course was uneventful. Neurologic exam was normal at stroke clinic follow-up 6 weeks later. To our knowledge, this is the first report of an ICVT associated with prothrombin gene mutation.

The Contribution of Inherited Thrombophilia to Venous Thromboembolism in Cancer Patients.

Although the relationship between venous thromboembolism (VTE) and cancer has been a subject of study, knowledge of the contribution of thrombophilia to thrombosis in patients with cancer is still very limited. The aim of this article is to collect present knowledge on the contribution of inherited thrombophilia to VTE in cancer patients. We performed a search in Google Scholar and PubMed and selected 21 from 76 returned articles. Then we made a narrative review of the selected articles. We describe 11 studies on the contribution of inherited thrombophilia to VTE in cancer patients in general and 10 on that contribution in specific types of cancer: 1 in colorectal cancer, 4 in breast cancer, 1 in gynecologic cancer and 4 in hematopoietic malignancies. All studies investigate the relation of factor V Leiden (FVL) to VTE, 13 that of the prothrombin G20210A mutation (PTG20210A) and 7 studies also investigate other inherited thrombophilias, such methylenetetrahydrofolate reductase gene mutations, although only 2 investigate the contribution of deficiencies of the natural anticoagulants. Studies are very heterogeneous, in design and sample size and conclusions differ considerably. There is no consensus on the contribution of inherited thrombophilia to VTE in cancer patients except for acute lymphoblastic leukemia in children. Probably, that contribution is not the same for all types of cancer and more studies are needed to bring more knowledge on this subject.

Do we need more guidance on thrombophilia testing? Challenges and special considerations.

INTRODUCTION: Thrombophilia testing (TT) is a laboratory procedure designed to detect the risk factors involved in the pathogenesis of vascular occlusions. The role of TT is also controversial because it has a limited impact on the choice and duration of antithrombotic treatments. AREAS COVERED: We reviewed, by examining MEDLINE up to October 2023. Accepted and not accepted thrombophilia markers are discussed along with the appropriateness or not of prescribing TT in several conditions such as: provoked and unprovoked venous thromboembolism (VTE), women who are planning a pregnancy whose relatives had VTE or have a hereditary thrombophilia, before assumption of estro-progestins, after multiple pregnant loss, arterial thrombosis, retinal vein occlusion, and splanchnic vein thrombosis. EXPERT OPINION: TT is not essential in the management of VTE, but it may be useful for limiting adverse events in case of thrombophilia. We expose our criticism of items afforded by other guidelines by presenting our opinion based on both the scientific evidence and clinical practice. We also deal with common mistakes in prescribing and interpretations of TT hoping to purpose an educational approach on this topic. Finally, we emphasize the creation of the expert in hemostasis and thrombosis who should be present in every hospital.

The risk of major bleeding in patients with factor V Leiden or prothrombin G20210A gene mutation while on extended anticoagulant treatment for venous thromboembolism.

BACKGROUND: Thrombophilia predisposes to venous thromboembolism (VTE) because of acquired or hereditary factors. Among them, it has been suggested that gene mutations of the factor V Leiden (FVL) or prothrombin G20210A mutation (PGM) might reduce the risk of bleeding, but little data exist for patients treated using anticoagulants. OBJECTIVES: To assess whether thrombophilia is protective against bleeding. METHODS: This multicentre, multinational, prospective cohort study evaluated adults receiving long-term anticoagulants after a VTE event. We analyzed the incidence of major bleeding as the primary outcome, according to the genotype for FVL and PGM (wild-type and heterozygous/homozygous carriers). RESULTS: Of 2260 patients with genotype testing, during a median follow-up of 3 years, 106 patients experienced a major bleeding event (17 intracranial and 7 fatal). Among 439 carriers of FVL, 19 experienced major bleeding and there were no differences between any mutation vs wild-type (hazard ratio [HR], 0.89 [0.53-1.49]; p = .66). The comparison of major bleeding events between the 158 patients with any-PGM mutation (heterozygous or homozygous) vs wild-type also showed a nonstatistically significant difference with HR of 0.53 (0.19-1.43), p = .21. However, multivariate analysis demonstrated that major bleeds or clinically relevant nonmajor bleeding were statistically less likely for patients with either FVL and/or PGM compared with patients with both wild-type factor V and prothrombin genes (HR, 0.73; 95% CI = 0.55-0.97; p = .03). CONCLUSION: This study demonstrates that thrombophilia, defined as the presence of either FVL or the prothrombin G20210A mutation, is related with a lower rate of major/clinically relevant nonmajor bleeding while on anticoagulants in the extended treatment for VTE.

Acute Myocardial Infarction in Patients with Hereditary Thrombophilia-A Focus on Factor V Leiden and Prothrombin G20210A.

Factor V (FV) Leiden and prothrombin G20210A are the most common hereditary thrombophilias. While their role in venous thromboembolism is well known, there are still uncertainties regarding their relationship with arterial thrombotic events, especially coronary ones. Our research, based on an in-depth analysis of the available literature, provides up-to-date information on the relationship between FV Leiden and prothrombin G20210A and acute myocardial infarction. FV Leiden and prothrombin G20210A screening should be implemented only in select cases, such as acute coronary syndrome in young individuals and/or in the absence of traditional cardiovascular risk factors and/or in the absence of significant coronary artery stenosis at angiography. Their identification should be followed by the implementation of optimal control of modifiable traditional cardiovascular risk factors to reduce the risk of recurrent events and genotyping and genetic counseling of all family members of affected cases for proper prophylaxis. An extended dual antiplatelet therapy (DAPT) may be considered, given the lower risk of bleeding under DAPT conferred by FV Leiden.

Prothrombin Gene Mutation as a Teaching Tool: An Autobiographical Case Report.

The prothrombin G20210A factor II mutation carrier status has been reported to cause complications during pregnancy. This report presents the case of a patient diagnosed with heterozygous prothrombin G20210A factor II mutation at 29 years of age during preconception genetic screening. The patient had two uncomplicated pregnancies. The patient underwent laparoscopic cholecystectomy with a complicated postoperative course. The complications included deep vein thrombophlebitis (DVT), portal vein thrombosis (PVT), and pulmonary embolization (PE). The treatment options and contraceptive choices are also discussed in this report. Our report discusses the subsequent risks inherent in a heterozygote following the administration of oral contraceptives, prolonged immobilization related to lower extremity trauma, and extended motor vehicle excursion.

Mean platelet volume as an effective biomarker for predicting high-risk patients of hereditary thrombophilia: A retrospective study.

OBJECTIVE: Literature shows evidence of the use of mean platelet volume (MPV) as a biomarker in thromboembolic conditions. It is recommended that genetic testing be performed selectively for hereditary thrombophilia. It might be useful to determine the priority of patients for genetic testing of hereditary thrombophilia through appropriate methods. We aimed to investigate the predictive value of MPV for high-risk patients of hereditary thrombophilia. METHODS: The hematologic (MPV), biochemical (antithrombin III, protein S, protein C), molecular genetic test results (factor V Leiden [FVL], and prothrombin G20210A [PT]) obtained retrospectively from medical files of 263 patients categorized into high- versus low-risk for thrombophilia were statistically analyzed and the value of MPV in predicting high-risk patients was assessed by receiver operating characteristic (ROC) analysis. RESULTS: The frequencies of high- versus low-risk patients were 45.2% and 54.8%, respectively. Significantly more high-risk patients (n=81) compared to low-risk patients had FVL (n=66) and PT mutations (n=80 vs. 34) (p<0.001). The MPV values in high-risk patients (mean=11.1 fl, range=7.8-13.6) were significantly higher than those in the low-risk patients (mean=8.6 fl, range=6-10.9) (p<0.001). The ROC curve analysis for MPV revealed a statistically significant area under the curve of 0.961 (95% confidence interval=0.931-0.981) at a cut-off point of 10.1 fl with a sensitivity of 89.1% and a specificity of 91.7% (p<0.001). CONCLUSION: MPV might be used as an effective biomarker to screen and select patients for genetic thrombophilia testing. Large multicenter studies are needed for recommending the inclusion of MPV in future guidelines for hereditary thrombophilia.

Congenital thrombophilia in East-Asian venous thromboembolism population: a systematic review and meta-analysis.

Background: Various inherited traits contribute to the overall risk of venous thromboembolism (VTE). In addition, the epidemiology of thrombophilia in the East-Asian VTE population remains unclear; thus, we aimed to assess the proportion of hereditary thrombophilia via a meta-analysis. Methods: Publications from PubMed, EMBASE, web of science, and Cochrane before December 30, 2022, were searched. Studies from Japan, Korea, China, Hong Kong, Taiwan, Singapore, Thailand, Vietnam, Myanmar, and Cambodia were included. Congenital thrombophilia was described as diseases including protein C (PC) deficiency, protein S (PS) deficiency, antithrombin (AT) deficiency, factor (F)V Leiden (FVL), and prothrombin G20210A mutations. Studies were selected by 2 reviewers for methodological quality analysis. A random-effects model was used for the meta-analysis, assuming that estimated effects in the different studies are not identical. Results: Forty-four studies involving 6453 patients from 7 counties/regions were included in the meta-analysis. The prevalence of PC, PS, and AT deficiencies were 7.1%, 8.3%, and 3.8%, respectively. Among 2924 patients from 22 studies, 5 patients were carriers of FVL mutation. Among 2196 patients from 10 studies, 2 patients were carriers of prothrombin G20210A mutation in a Thailand study. Conclusion: The prevalence of PC, PS, and AT deficiencies was relatively high, while a much lower prevalence of FVL and prothrombin G20210A mutations were identified in East-Asian patients with VTE. Our data stress the relative higher prevalence of PC, PS, and AT deficiencies for thrombophilia in the East-Asian VTE population.

The Combined Heterozygosity of Factor V Leiden and G20210A Prothrombin Gene Mutation in a Patient With Venous Thromboembolism.

Venous thromboembolism (VTE) is a chronic illness that includes pulmonary embolism (PE) and deep vein thrombosis (DVT), and many risk factors are associated. Anticoagulation therapy remains the cornerstone of venous thromboembolism management, and the duration of anticoagulation depends on the risk of venous thromboembolism. We report a case of a female with a combined heterozygosity of factor V Leiden and G20210A prothrombin gene mutation.

Testing for Factor V Leiden (FVL) and Prothrombin G20210A Genetic Variants.

Laboratory testing for Factor V Leiden and Prothrombin G20210A genetic variants permits defining the increased relative risk for venous thromboembolism in selected patients. Laboratory DNA testing for these variants may be undertaken by a variety of methods, including fluorescence-based quantitative real-time PCR (qPCR). This is a rapid, simple, robust, and reliable method to identify genotypes of interest. This chapter describes the method that employs PCR amplification of the patient DNA region of interest and genotyping by allele-specific discrimination technology on a quantitative real-time PCR (qPCR) instrument.

Central retinal artery occlusion and subsequent amaurosis fugax in the contralateral eye associated with the G20210A prothrombin gene (F2) variant: a case report.

PURPOSE: Report the case of a patient with a history of central retinal artery occlusion in her right eye and amaurosis fugax associated with acute ischemic changes in her left eye related to a prothrombin G20210A gene variant, in which OCT-A was used as a diagnostic and therapeutic tool. CASE PRESENTATION: 55-year-old woman with a history of central retinal artery occlusion in her right eye and prothrombin gene G20210A (F2) variant diagnosis. She presented to our consultation with amaurosis fugax in her left eye. As medical history, she had an episode of bilateral posterior scleritis diagnosed asynchronously with the current episode. Vascular, autoimmune, and metabolic prothrombotic diseases were ruled out. OCT-A showed areas suggesting acute ischemia consistent with macular retinopathy in her left eye. Anticoagulant therapy with Apixaban was initiated, considering the risk for her vision. Control OCT-A showed perfusion improvement in the previous site of the occlusive vascular event. We also considered the extent of the inflammatory response due to posterior scleritis as a differential diagnosis. Nevertheless, it is less likely, considering the temporality between scleritis and the retinal-vascular episodes. CONCLUSIONS: While the G20210A prothrombin gene (F2) variant is a rare cause of retinal artery occlusion, it is important to consider it a differential diagnosis. Good visual outcomes can be achieved with prompt initiation of antithrombotic treatment. In addition, OCT-A is useful for diagnosing ischemic retinal changes that cannot be observed with other diagnostic methods and monitoring them.

Association of Inherited Thrombophilia with Recurrent Pregnancy Loss in A Population of Lebanese Women: A Case Control Study.

Recurrent pregnancy loss (RPL) complication is a challenge of reproductive medicine due to its often unknown etiology.
A case-control study was carried out between June 2019 and April 2020 to examine the correlation between RPL
and inherited thrombophilia (IT), namely mutations in factor V Leiden (FVL G1691A), prothrombin (FII G20210A),
and methylenetetrahydrofolate reductase (MTHFR C677T). A total of 120 Lebanese women with RPL was studied
and compared, for the frequency of these mutations, to 100 healthy reproductive Lebanese women. The association
between the zygosity status of the three tested mutations, the existence of more than one prothrombotic single nucleotide
polymorphisms (SNPs), and the increased risk of RPL were examined using Chi-square or two-tailed fisher exact
test, and the student t test. The predictive factors of RPL were analyzed using a multiple logistic regression model.
P<0.05 was considered to be statistically significant. Our results showed statistically significant higher frequencies
of FVL G1691A and FII G20210A mutations among the cases with RPL compared to the control group. Thus, RPL is
associated with FVL G1691A and FII G20210A mutations. These mutations seem to increase the risk of RPL in the
Lebanese women. Therefore, we suggest thrombophilia screening and adequate genetic counseling for women with
RPL and at high-risk to plan for primary prevention, avoiding thromboembolic or obstetric accidents, and reducing
the associated morbidity and mortality among Lebanese women.