The prevalence of factor V R506Q mutation-Leiden among apparently healthy Lebanese

Mapping the Diverse Genetic Disorders and Rare Diseases Among the Syrian Population: Implications on Refugee Health and Health Services in Host Countries

The aim of this systematic review is to provide physicians and researchers with a comprehensive list of reported genetic disorders in patients of Syrian origin-those who have become part of the largest displaced population globally-and to highlight the need to consider migrant population-based risk for the development of genetic disease control and prevention programs. This review was performed based on the 2015 PRISMA and the international prospective register of systematic reviews. The present review reports on a total of 166 genetic disorders (only 128 reported on OMIM) identified in the Syrian population. Of these disorders, 27% are endocrine-, nutritional- and metabolic-related diseases. Second to metabolic disorders are congenital malformations, deformations and chromosomal abnormalities. Diseases of the blood and the blood-forming organs accounted for 13% of the total genetic disorders. The majority of the genetic disorders reported in Syrian patients followed an autosomal recessive mode of inheritance. These findings are a reflection of the high rates of consanguineous marriages that favor the increase in incidence of these diseases. From the diseases that followed an autosomal recessive mode of inheritance, 22% are reported to be only present in Syria and other regional countries. Twelve of these genetic diseases were identified to be strictly diagnosed in individuals of Syrian origin. The present systematic review highlights the need to develop programs that target genetic disorders affecting Syrian migrants in host countries. These programs would have potential financial and economic benefits, as well as a positive impact on the physical and mental health of members of the Syrian refugee community and those of their host societies. In turn, this would decrease the burden on the health systems in host countries.

Should we screen Eastern Mediterranean COVID-19 patients for inherited thrombophilia?

The inflammatory component of Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) creates a pro-thrombotic state that necessitates a thrombophylactic strategy for hospitalized patients. Such strategies are difficult to be standardized because certain individuals can have pro-thrombotic conditions, such as inherited thrombophilia, which pre-dispose them to an additional coagulative risk. Whether outside the hospital or when admitted, patients with inherited thrombophilia need special anticoagulant and antiplatelet attention. Identifying such patients, especially in susceptible populations like the eastern Mediterranean (EM) region, will aid primary providers in risk stratification for choosing the optimal anticoagulation or antiplatelet plan.

High prevalence of factor V Leiden and prothrombin G20101A mutations in Kashmiri patients with venous thromboembolism

AIM

The genetic variants of the factor V (G1691A), prothrombin (G20210A) and MTHFR (C677T) genes have been widely implicated as inherited risk factors for developing venous thrombosis. This study was undertaken to reveal the frequency of these mutations in Kashmiri patients with venous thromboembolism.

METHODOLOGY

A case-control study was designed with 250 VTE patients and 250 healthy controls. The mutations were analysed using ARMS-PCR and PCR-RFLP approach.

RESULT

The factor V Leiden G1691A mutation was found in 17/250 (6.8%) VTE patients and prothrombin G20210A mutation was found in 7/250 (2.8%) VTE patients while no mutation was found in any of the healthy controls. Both the mutations were found to be significantly associated with the increased risk of VTE (p = 0.0001 and 0.0150 respectively) while no association of VTE risk with MTHFR C677T polymorphism was found (p = 0.53).

CONCLUSION

The increased frequency of factor V Leiden G1691A and prothrombin G20210A mutation in VTE patients indicates a significant role of these mutations in the development of VTE in our population. We therefore suggest the routine screening of these two mutations as thrombophilic markers in Kashmiri patients with venous thromboembolism.

Genetic Risk Factors of Venous Thromboembolism in the East Algerian Population

Many genetic risk factors have been identified for causing venous thromboembolism (VTE). Most of them affect the function of natural anticoagulant pathways, particularly the protein C system, although recent studies suggest a role of components of the hematopoietic pathway in the etiology of venous thrombosis. In this case–control study, we aimed to determine the frequency of prothrombin G20210A and factor V Leiden (FVL) G1691A polymorphisms and protein C, protein S, and antithrombin III deficiencies in the East Algerian population and to investigate whether these genetic factors are associated with VTE. On the other hand, our study tends to evaluate the status of JAK2V617F and calreticulin (CALR) mutations among these cases. The participants consisted of 121 cases with VTE and 146 healthy controls. Polymorphisms of FVL G1691A and prothrombin G20210A were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism. JAK2-V617F and calreticulin mutations were analyzed by quantitative PCR and PCR followed by capillary electrophoresis sequencing, respectively. Protein C, protein S, and antithrombin levels were determined and then hereditary deficiencies were identified. Of all cases and controls, none was a carrier of the antithrombin III deficiency, prothrombin gene G20210A, and CALR mutations. Only 1 case reported having a positive JAK2 mutation (mutant allele burden was 15%). The FVL mutation (GA/AA) was found in 14 (11.6%) cases and 2 (1.4%) controls and it was significantly different between both the groups ( P = .001). Deficiencies of protein S and protein C were detected in 17 (18.8%) cases. The univariate analysis resulted in a significant impact of FVL (odds ratio [OR] = 9.4, 95% confidence interval [CI] = 2.1-42.3; P = .003) and of protein S deficiency (OR = 16.9, 95% CI =2.1-132.8, P = .007) on the VTE status. Both factors stayed significant after adjustment for sex and age. The OR of the protein C deficiency was slightly elevated (OR = 6.4, 95% CI = 0.7-55.5), but it did not reach the level of statistical significance ( P = .091), and it was therefore not considered as a risk factor. In conclusion, coagulant factor V gene G1691A mutation and protein S deficiency constitute important genetic risk factors in patients with VTE in Eastern Algeria. The somatic mutation of JAK2 V617F and CALR mutations are less frequent causes of VTE, thus routine testing for these mutations is not recommended.

The Frequency of Factor V Leiden and Concomitance of Factor V Leiden With Prothrombin G20210A Mutation and Methylene Tetrahydrofolate Reductase C677T Gene Mutation in Healthy Population of Denizli, Aegean Region of Turkey

Factor V Leiden causing activated protein C resistance is the most common inherited form of thrombophilia leading to thrombosis. Its frequency shows great ethnic and geographic variations. The aim of this study was to determine the frequency of FV Leiden and coinheritance of FV Leiden with two other frequent hereditary thrombophilia causes, namely, prothrombin G20210A and methylene-tetrahydrofolate reductase ( MTHFR) C677T mutation in the Aegean region of Turkey. The study population consisted of 1030 (500 men and 530 women) apparently healthy subjects. Functional resistance to activated protein C (APC) was measured by using the test kit STA staclot APC-R ((Diagnostica Stago, Asnieres, France, Cat. No. 00721). In subjects with APC resistance, molecular analyses of FV Leiden and of prothrombin G20210A and MTHFR C677T mutation were performed by using FV-PTH-MTHFR StripA (Vienna Lab, Labordiagnostika GmbH, Austria) kit, which was based on hybridization of polymerase chain reaction (PCR) amplified DNA products with mutation-specific oligonucleotide probes. Functional APC resistance was present in 93 subjects (9%). FV Leiden mutation was found in 87 of 93 subjects with APC resistance by PCR method. The FV Leiden carrier frequency was found to be 8.4% (87/1030). Seventy-six individuals were heterozygous (7.3%), and 11 were homozygous (1.06%). Among the 87 subjects with FV Leiden mutation, 45 subjects had MTHFR C677T gene mutation (7 homozygous, 38 heterozygous) and 4 subjects had heterozygote prothrombin G20210A gene mutation. A combination of FV Leiden and prothrombin G20210A and MTHFR C677T gene mutation was detected in 3 subjects. The results indicate that FV Leiden prevalence is quite high and coexistence of FV Leiden with other hereditary causes of thrombosis such as prothrombin G20210A mutation and MTHFR enzyme defect is not rare in healthy population of Aegean region of Turkey.

To determine the frequency of Factor V Leiden in cases of Deep Vein Thrombosis and Healthy controls

Objective:

To determine the frequency of Factor V Leiden in cases of Deep Vein Thrombosis and Healthy controls.

Methods:

This case control study was performed in Armed Forces Institute of Pathology Rawalpindi, From 21^st March to 25^th September 2013. One hundred patients with diagnostic evidence of Deep vein thrombosis on Doppler ultrasound/Magnetic resonance imaging (MRI) scan were included in the study through non probability convenient sampling and compared with 100 matched healthy controls. DNA was extracted from the blood sample by kit method. In order to identify Factor V Leiden mutation, the polymerase chain reaction (PCR) method was utilized combined with the Amplification refractory mutation system. Data was analyzed using statistical package for social sciences (SPSS) version 17.

Results:

In 100 patients of Deep Vein Thrombosis (DVT), frequency of Factor V Leiden (FVL) was 13% and it is was 2% in healthy control group. A significant association was found between FVL and DVT with odds ratio of 7.32 and with P value (P = 0.003).

Conclusion:

FVL was found to be highly prevalent among patients of DVT, Signifying strong association between the two.

Prenatal genetic testing for familial severe congenital protein C deficiency

Severe congenital protein C (PC) deficiency is an autosomal recessive hereditary thrombophilia caused by mutations in PROC. The case manifested severe purpura fulminans, intracranial thrombosis or hemorrhage within 4 days after birth, resulting in blindness. We report the identification of inherited compound heterozygous mutations, including a novel nonsense mutation in PROC, and a prenatal genetic test for a subsequent pregnancy. Prenatal diagnosis may facilitate preemptive and radical therapy for severe PC deficiency.

High Incidence of ACE/PAI-1 in Association to a Spectrum of Other Polymorphic Cardiovascular Genes Involving PBMCs Proinflammatory Cytokines in Hypertensive Hypercholesterolemic Patients: Reversibility with a Combination of ACE Inhibitor and Statin

Cardiovascular diseases (CVDs) are significantly high in the Lebanese population with the two most predominant forms being atherosclerosis and venous thrombosis. The purpose of our study was to assess the association of a spectrum of CVD related genes and combined state of hypertension hypercholesterolemia (HH) in unrelated Lebanese. Twelve polymorphisms were studied by multiplex PCR and reverse hybridization of DNA from 171 healthy individuals and 144 HH subjects. Two genes were significantly associated with HH: ACE (OR: 9.20, P<0.0001) and PAI-1 (OR: 2.29, P = 0.007), respectively with the occurrence of the risky alleles “Del” and “4G”. The frequencies of the Del and 4G alleles were found to be 0.98 and 0.90 in the HH group versus 0.84 and 0.79 in the healthy group, respectively. Serum ACE activity and PAI-I increased significantly with Del/Del and 4G/5G genotypes. The co-expression of Del/4G(+/+) was detected in 113 out of 171 (66.0%) controls and 125 out of 144 (86.8%) HH subjects. Del/4G(-/-) was detected in only 6 (3.5%) controls and undetected in the HH group. Three venous thrombosis related genes [FV(Leiden), MTHFR(A1298C) and FXIII(V34L)] were significantly related to the prominence of the co-expression of Del/4G(+/+). A range of 2 to 8 combined polymorphisms co-expressed per subject where 5 mutations were the most detected. In Del/4G(+/+) subjects, peripheral blood mononuclear cells (PBMCs) produced significant elevated levels of IFN-γ and TNF-α contrary to IL-10, and no variations occurred for IL-4. ACE inhibitor (ramipril) in combination with statin (atorvastatin) and not alone reversed significantly the situation. This first report from Lebanon sheds light on an additional genetic predisposition of a complex spectrum of genes involved in CVD and suggests that the most requested gene FVL by physicians may not be sufficient to diagnose eventual future problems that can occur in the cardiovascular system. Subjects expressing the double mutations (Del/4G) are at high risk for the onset of CVDs.

Factor V Leiden 1691G/A and prothrombin gene 20210G/A polymorphisms as prothrombotic markers in adult Egyptian acute leukemia patients

Factor V Leiden 1691G/A and prothrombin gene 20210G/A mutations are the most common genetic defects leading to thrombosis. This work aimed to study the FV Leiden and the prothrombin gene polymorphism in adult Egyptian patients with acute leukemia and their importance in thrombophilia screening. The study included 76 patients with acute leukemia and 100 healthy controls. Genotyping was done by real-time polymerase chain reaction technique. For factor V Leiden, the frequency of G/A mutation conferred more than 2.5-fold of increased risk of (OR 2.639 95 % CI 1.045-6.669). The frequency of factor V Leiden combined (G/A + A/A) genotypes conferred 2.83-fold of increased risk (OR 2.828, CI 1.13-7.075), The A allele conferred almost threefold increased risk (OR 2.824, 95 % CI 1.175-6.785). Despite higher frequency in patients compared to controls, there was no risk of association between prothrombin gene mutation and acute leukemia in adult Egyptians nor was there between combined genotypes of prothrombin gene mutation and factor V Leiden.

Influence of acquired and genetic risk factors on the prevention, management, and treatment of thromboembolic disease

Prevention, management, and treatment of venous thromboembolism requires understanding of the epidemiology and associated risk factors, particularly in recognizing populations warranting prophylaxis, in evaluating patients with high risk situations, and in determining the duration of anticoagulation required to minimize recurrent thrombosis and to avoid postthrombotic syndrome. The present paper reviews recent advances concerning acquired and genetic risk factors for venous thrombosis, analyses individual risks related to age, and focuses on thrombotic genetic risk factors and the synergistic gene-environment and gene-gene interactions and their importance in the management and treatment of venous thromboembolic disease.

Factor V Leiden does not have a role in cryptogenic ischemic stroke among Iranian young adults

BACKGROUND

Different risk factors have been suggested for ischemic stroke in young adults. In a group of these patients despite of extensive diagnostic work-up, the primary cause remains unknown. Coagulation tendency is accounted as a possible cause in these patients. Previous studies on factor V Leiden (FVL) as the main cause of inherited thrombophilia for clarifying the role of FVL in stroke have resulted in controversial findings. The current study investigates the role of this factor in ischemic stroke among Iranians.

MATERIALS AND METHODS

This case-control study was performed between September 2007 and December 2008 in Isfahan, Iran. The case group comprised of 22 patients of which 15 were males and 7 were females with age range of ≤50 years, diagnosed as ischemic stroke without classic risk factors and the control group consisted of 54 healthy young adults. After filling consent form, venous blood samples were obtained and sent to the laboratory for genetic examination.

RESULTS

No FVL mutation was found in the case group. There was one carrier of the mutation as heterozygous in the control group (relative frequency = 1.85%).

CONCLUSIONS

Based on our study, FVL might not be considered as an independent risk factor for ischemic stroke in Iranian individuals who are not suffering from other risk factors of ischemic stroke.

Clinical Presentation and Outcome of Mesenteric Vein Thrombosis

Mesenteric venous thrombosis (MVT) is an uncommon event. We retrospectively analyzed data for patients who were admitted with MVT between June 2005 and May 2012 in Qatar. The study included 35 patients with a mean age of 45 ± 11 years. The risk of MVT was significantly high among males who smoked and females of Arab ethnicity. The main manifestations of MVT were abdominal distension and vomiting. The major etiological factors included deficiency in protein C and S, homocysteinemia, and prior abdominal surgery. Computed tomography (CT) findings were helpful in 80% of the patients. Bowel resection with primary anastomosis was performed in 25 (71%) patients. The overall mortality rate was 17%. High index of suspicion, detection of risk factors, CT imaging, and timely intervention are essential for better prognosis.

The Effect of Lactic Acid Bacteria-fermented Soybean Milk Products on Carrageenan-induced Tail Thrombosis in Rats

Thrombosis is characterized by congenital and acquired procatarxis. Lactic acid bacteria-fermented soybean milk products (FS-LAB) inhibit hepatic lipid accumulation and prevent atherosclerotic plaque formation. However, the therapeutic efficacy of FS-LAB against thrombosis has yet to be investigated. In this study, FS-LAB were administered subcutaneously into the tails of rats, with the subsequent intravenous administration of κ-carrageenan 12 hr after the initial injection. In general, administration of κ-carrageenan induces thrombosis. The length of the infarcted tail regions was significantly shorter in the rats administered a single-fold or double-fold concentration of the FS-LAB solution compared with the region in control rats. Therefore, FS-LAB exhibited significant antithrombotic effects. Our study is the first to characterize the properties of FS-LAB and, by testing their efficacy on an in vivo rat model of thrombosis, demonstrate the potency of their antithrombotic effect.

Behçet's Disease, Associated Large Vessel Thrombosis, and Coexistent Thrombophilia: A Distinct Nosological Entity?

Behçet's disease (BD) represents a multisystemic disorder that combines features of immune-mediated diseases and autoinflammatory disorders. Even though it is recognized that every type or size of vessel can be affected in this disease, there is an inability to describe a coherent model that sufficiently explains the predilection of certain patients with BD for manifesting severe large vessel thrombosis. The inconsistent epidemiologic data and the complex genetic background of BD, along with the controversy of multiple international studies regarding the coexistence of thrombophilia in patients with BD and large vessel thrombosis, make us think that a percentage of these patients may actually suffer from a distinct clinical entity. The stimulus for this concept arose from the clinical observation of three male patients who were admitted to our clinic due to extended vena cava thrombosis. On the occasion of those clinically and laboratory resembling cases, we performed a literature review concerning the epidemiology of BD, associated thrombosis, and coexistent thrombophilic factors, in order to present some evidence, which sustains our hypothesis that certain patients with large vessel thrombosis, who share features of BD and coexistent thrombophilia, should actually be further investigated for the possibility of suffering from a distinct nosological entity.

Polymorphisms in Factor II and Factor V thrombophilia genes among Circassians in Jordan

Thrombosis is a major cause of morbidity and mortality worldwide. Genetic factors are one component of thrombosis. We studied the prevalence of two mutations that are known risk factors in the pathogenesis of arterial and venous thrombosis in the genetically isolated Circassian population in Jordan. Factor II G20210A and Factor V Leiden single nucleotide polymorphisms were analysed by polymerase chain reaction and restriction fragment length polymorphism method in 104 random unrelated subjects from the Circassian population in Jordan. The prevalence rates among the Circassian population in Jordan for Factor II G20210A was 12.2% and for Factor V Leiden was 7.7%. We have shown that the population is in Hardy-Weinberg equilibrium and that the prevalences of both mutations are within the range of other ethnic groups. This is the first study to describe Circassian health related genetic characteristics in Jordan. Such population-based studies will contribute to understanding the interaction between genetic and environmental risk factors. It will remain to be seen whether carriers of Factor II G20210A and Factor V Leiden are more likely to develop thrombosis. This issue should be studied in the future to determine the need for screening of these mutations particularly in thrombophilia patients.

Factor V-Leiden Mutation: A Common Risk Factor for Venous Thrombosis among Lebanese Patients

Aim. Lebanon exhibits one of the highest prevalences of factor V-Leiden (FVL) in the world (14.4%). The aim of this study is to evaluate the incidence of FVL mutation among Lebanese patients with lower extremity venous thrombosis. Material and Methods. From January 2003 to January 2011, 283 consecutive Lebanese patients, diagnosed with deep venous thrombosis (DVT) by duplex scan, were retrospectively reviewed. FVL mutation was tested among patients with conditions highly suggestive of hypercoagulation states (65 patients). Results. FVL mutation was detected among 56.9% of patients, 68.6% of patients younger than 50 years, and 43.4% of patients older than 50 years (P = 0.041). FVL mutation was commonly reported in young adults, in patients with pregnancy, estrogen drugs, recurrent DVT, and resistance to anticoagulation. Conclusion. The high rate of FVL mutation observed among Lebanese patients with venous thrombosis is related to the high prevalence of this mutation in the Lebanese population. Thrombophilia screening should be tailored to accommodate a population's risk factor. In countries with high prevalence of FVL, this mutation should be screened among patients younger than 50 years and patients with situations highly suggestive of hypercoagulation states.

Lower extremity venous thrombosis in patients younger than 50 years of age

Aim

Lower extremity deep venous thrombosis in the young adult is uncommon and has not been well studied in the literature. The aim of this study is to define risk factors for deep venous thrombosis among patients younger than 50 years of age, to compare them with a control group, and to suggest recommendations for the management and treatment of venous thrombosis in this particular group of patients.

Methods

From January 2003 to January 2011, 66 consecutive Lebanese patients (29 males and 37 females) younger than 50 years, diagnosed in an academic tertiary-care center with lower extremity deep venous thrombosis by color flow duplex scan, were retrospectively reviewed. Their age varied between 21 and 50 years (mean 38.7 years). The control group included 217 patients (86 males and 131 females) older than 50 years (range: 50–96 years; mean 72.9 years).

Results

The most commonly reported risk factors in the younger age group were inherited thrombophilia (46.9% compared with 13.8% in the control group; P < 0.001), pregnancy (18.2% compared with 0.5%; P < 0.001), treatment with estrogen drugs (13.6% compared with 2.3%; P = 0.001), and family history of venous thromboembolism (9.1% compared with 3.8%; P = 0.084).

Conclusion

Inherited thrombophilia is the most commonly observed risk factor among patients younger than 50 years, with a prevalence of three times more than the control group. Young adults should be screened for thrombophilia even in the presence of transient acquired risk factors. Pregnancy and treatment with estrogen drugs essentially when associated with inherited thrombophilia represent a frequent cause of venous thrombosis among young female patients. Inferior vena cava abnormalities should be excluded in young patients with spontaneous proximal venous thrombosis especially when recurrent venous thrombosis or resistance to anticoagulation are observed.

Factor V Leiden thrombophilia

Factor V Leiden is a genetic disorder characterized by a poor anticoagulant response to activated Protein C and an increased risk for venous thromboembolism. Deep venous thrombosis and pulmonary embolism are the most common manifestations, but thrombosis in unusual locations also occurs. The current evidence suggests that the mutation has at most a modest effect on recurrence risk after initial treatment of a first venous thromboembolism. Factor V Leiden is also associated with a 2- to 3-fold increased relative risk for pregnancy loss and possibly other obstetric complications, although the probability of a successful pregnancy outcome is high. The clinical expression of Factor V Leiden is influenced by the number of Factor V Leiden alleles, coexisting genetic and acquired thrombophilic disorders, and circumstantial risk factors. Diagnosis requires the activated Protein C resistance assay (a coagulation screening test) or DNA analysis of the F5 gene, which encodes the Factor V protein. The first acute thrombosis is treated according to standard guidelines. Decisions regarding the optimal duration of anticoagulation are based on an individualized assessment of the risks for venous thromboembolism recurrence and anticoagulant-related bleeding. In the absence of a history of thrombosis, long-term anticoagulation is not routinely recommended for asymptomatic Factor V Leiden heterozygotes, although prophylactic anticoagulation may be considered in high-risk clinical settings. In the absence of evidence that early diagnosis reduces morbidity or mortality, decisions regarding testing at-risk family members should be made on an individual basis.

The Role of Factor V Leiden in Adult Patients With Venous Thromboembolism: A Meta-Analysis of Published Studies from Turkey

Factor V Leiden (FVL) is the most common inherited risk factor for venous thromboembolism (VTE). The frequency of FVL in patients with VTE has been reported from different parts of Turkey. A meta-analysis was performed to estimate the risk of VTE associated with FVL in Turkish population. Published studies were retrieved from Pubmed and Science Citation Index/Expanded. We selected studies comparing the prevalence of FVL in patients with VTE with controls. The analysis was performed by the software comprehensive meta-analysis. The analysis consisted of 10 studies including 1202 patients with VTE and 1283 controls. The pooled frequency of FVL was significantly higher in patients with VTE (22.8%) than controls (7.6%). The pooled odds ratio (OR) was 3.4 (95% confidence interval [CI], 2.6-4.5). The study showed homogeneity ( Q value, 9.955). No publication bias was observed in any comparison model. Our meta-analysis showed an association of FVL with VTE in Turkey.

Association of inherited thrombophilia with recurrent pregnancy loss in palestinian women

Objective. This study aimed at analyzing the association between recurrent pregnancy loss (RPL) and factor V G1691A (FVL), prothrombin G20210 (FII); and MTHFR C677T (MTHFR) in Palestinian women. Method. We studied 329 Palestinian women with RPL and/or stillbirth (SB); and compared them to 402 healthy reproductive Palestinian women. Cases and controls were tested for the above mutations. Odds ratio (OR) at confidence interval (CI) of 95% was used as a measure of association between the mutations and RPL. Results. Our statistical analysis showed a slightly increased association, which was not significant between FVL and RPL (OR 1.32, 95% CI 0.90-1.94), and no association between FII (OR 0.84, 95% CI 0.38-1.92), MTHFR (OR 0.58, 95% CI 0.32-1.03), and RPL. Further analysis of RPL subgroups revealed an association between FVL and first-trimester loss (OR 1.33, 95% CI 0.892-1.989), and second-trimester loss (OR 1.13, 95% CI 0.480-2.426), both were not statistically significant. Furthermore, the only statistically significant association was between FVL and SB (OR 2.0, 95% CI 1.05-3.70). Conclusion. Our analysis had failed to find a significant association between FVL, FII, MTHFR; and RPL in either the first or second trimester. FVL was significantly associated with fetal loss if the loss was a stillbirth.

Hormonal contraception and thrombotic risk: a multidisciplinary approach

Heightened publicity about hormonal contraception and thrombosis risk and the publication of new guidelines by the World Health Organization in 2009 and the Centers for Disease Control and Prevention in 2010 addressing this complex issue have led to multidisciplinary discussions on the special issues of adolescents cared for at our pediatric hospital. In this review of the literature and new guidelines, we have outlined our approach to the complex patients referred to our center. The relative risk of thrombosis on combined oral contraception is three- to fivefold, whereas the absolute risk for a healthy adolescent on this therapy is only 0.05% per year. This thrombotic risk is affected by estrogen dose, type of progestin, mechanism of delivery, and length of therapy. Oral progestin-only contraceptives and transdermal estradiol used for hormone replacement carry minimal or no thrombotic risk. Transdermal, vaginal, or intrauterine contraceptives and injectable progestins need further study. A personal history of thrombosis, persistent or inherited thrombophilia, and numerous lifestyle choices also influence thrombotic risk. In this summary of one hospital's approach to hormone therapies and thrombosis risk, we review relative-risk data and discuss the application of absolute risk to individual patient counseling. We outline our approach to challenging patients with a history of thrombosis, known thrombophilia, current anticoagulation, or family history of thrombosis or thrombophilia. Our multidisciplinary group has found that knowledge of the guidelines and individualized management plans have been particularly useful for informing discussions about hormonal and nonhormonal options across varied indications.

Is thrombophilia a major risk factor for deep vein thrombosis of the lower extremities among Lebanese patients?

Aim

Factor V Leiden (R506Q) mutation is the most commonly observed inherited genetic abnormality related to vein thrombosis. Lebanon has one of the highest frequencies of this mutation in the world with a prevalence of 14.4% in the general population. The aim of this study is to define risk factors including inherited genetic abnormalities among Lebanese patients with lower extremity deep vein thrombosis. We report the clinical outcome of patients with thrombophilia.

Methods

From January 1998 to January 2008, 162 patients (61 males and 101 females) were diagnosed with lower extremity deep vein thrombosis. Mean age was 61 years (range: 21 to 95 years).

Results

The most frequent risk factors for vein thrombosis were surgery, advanced age, obesity, and cancer. Twenty-five patients had thrombophilia, 16 patients had factor V Leiden (R506Q) mutation, and seven patients had MTHFR C677T mutation. Ninety-two percent of patients screened for thrombophilia were positive. Screening was requested in young patients (16), patients with recurrent (11), spontaneous (8), and extensive (5) venous thrombosis, familial history (5), pregnancy (4), estroprogestative treatment (3), and air travel (1). Nine patients had one, 11 patients had two, and five had three of these conditions. Follow-up (6 to 120 months) of these 25 patients treated with antivitamin K did not reveal recurrences or complications related to venous thromboembolism.

Conclusion

Factor V Leiden mutation followed by MTHFR mutation are the most commonly observed genetic abnormalities in these series. Defining risk factors and screening for thrombophilia when indicated reduce recurrence rate and complications. Recommendations for thrombophilia screening will be proposed.

The Prevalence of Methylenetetrahydrofolate Reductase 677 C-T, Factor V 1691 G-A, and Prothrombin 20210 G-A Mutations in Healthy Populations in Sétif, Algeria

The polymorphic mutation 677 C-T in the methylenetetrahydrofolate reductase (MTHFR) gene presents a heterogeneous worldwide distribution and is associated with different disorders such as cardiovascular disease. Its frequency shows great ethnic and geographic variations. The aim of this work is to determine the frequency of MTHFR 677 C-T and coexistence of MTHFR 677 C-T with 2 other common, hereditary thrombophilia causes—namely, factor V 1691 G-A and prothrombin (PT) 20210 G-A mutation—in the Sétif region of Algeria. The study involved 147 apparently healthy participants (82 men and 65 women). Genotyping was carried out by a real-time polymerase chain reaction. The MTHFR 677T carrier frequency was found to be 54.4% (80/147); 59 individuals were heterozygous (40.1%), and 21 were homozygous (14.3%). The frequency of MTHFR 677T was found to be 34.3%. Among the 147 individuals, 3 (2.0%) had factor V Leiden, and 5 (3.4%) had PT 20210 A mutation. Of the 80 participants with MTHFR 677T mutation, 2 had heterozygote factor V 1691 G-A gene mutation, and 4 had heterozygote PT 20210 G-A gene mutation. The results showed that MTHFR 677T prevalence is quite high: an allelic frequency of 34.3% with a genotype frequency of 14.3%. Factor V 1691 G-A and PT 20210 G-A gene mutations are rare in the healthy population of the Sétif region of Algeria.

Prevalence of factor V Leiden (G1691A) and prothrombin (G20210A) among Kurdish population from Western Iran

BACKGROUND

The mutation in factor V (FV) G1691A, known as factor V Leiden, and prothrombin (FII) gene G20210A are the two most prevalent causes of inherited thrombophilia. The present study reports the prevalence of factor V Leiden and the prothrombin G20210A gene mutations among healthy individuals of Kurdish ethnic background in Western Iran.

METHODS

Four hundred thirty-four healthy unrelated individuals, 255 male and 179 female, with a mean age of 28.7+/-15.5 from the Kermanshah Province of Iran were studied for prothrombin G20210A mutation. The factor V Leiden mutation was studied in 404 healthy individuals, of whom 232 were male and 172 were female. The factor V Leiden and prothrombin G20210A were detected by polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) method using Mnl I and Hind III restriction enzymes, respectively.

RESULTS

Among 434 individuals studied for prothrombin G20210A mutation seven carried this mutation as heterozygous (four female subjects and three male), giving a prevalence of 1.6% [95% confidence intervals (CI) 0.5-2.7) and an allele frequency of 0.8%. No homozygous prothrombin 20210AA was found. Factor V G1691A mutation was detected as heterozygous in 11 of 404 healthy individuals (five female and six male) and as homozygous in one male indicating a prevalence of 2.97% (95% CI 1.3-4.6) and allele frequency of 1.6%.

CONCLUSIONS

Our results indicated that the factor V Leiden and prothrombin G20210A mutations are not rare among populations of Western Iran and that the relationship between venous thrombophilia and these mutations have to be further studied in Western Iran population, which, in turn, may suggest a causal effect.

Genetics of coagulation: considerations for cardiac surgery

Genetic variants in the coagulation system have been known since antiquity. Today, because of modern improvements in diagnosis and medical management, the clinician is likely to encounter a spectrum of coagulation factor deficiencies and identified polymorphic variants in the surgical population. Because perioperative hemorrhagic and thrombotic complications are potentially serious, it is important to understand the role that these defects and variants may play in predicting risk and optimizing patient management. The implications of coagulation genetics on the perioperative management of the cardiac surgery patient are reviewed.

Prevalence of factor V Leiden, prothrombin and methylene tetrahydrofolate reductase mutations in women with adverse pregnancy outcomes in Lebanon

OBJECTIVE

The purpose of this study was to determine the prevalence of factor V Leiden, prothrombin, and methylene tetrahydrofolate reductase gene mutations in women with adverse pregnancy outcome compared with women who had uneventful pregnancies.

STUDY DESIGN

Between 2003 and 2005, pregnant women with > or = 1 unexplained second trimester abortion, > or = 1 intrauterine fetal death, severe preeclampsia, or severe intrauterine growth restriction (study subjects) were compared with control subjects (uneventful pregnancy) for the frequency of the mutations.

RESULTS

The cases of 91 patients in each arm were analyzed. Obstetric complications were second trimester abortions (16.5%), intrauterine fetal death (53.8%), preeclampsia (8.8%), and severe intrauterine growth restriction (20.9%). Study subjects were more likely to be older and multiparous compared with control subjects. The 2 groups showed no difference in the incidence of smoking or family history of thrombosis, but study subjects were more likely to have a positive family history of obstetric complications. The prevalence of factor V Leiden (12.1% vs 18.7%; P = .304), prothrombin (7.7% vs 5.5%; P = .765), methylene tetrahydrofolate reductase gene mutations (53.8% vs 65.9%; P = .130), and > 1 mutation (11.0% vs 17.6%; P = .290) was not significantly different between study subjects and control subjects.

CONCLUSION

Factor V Leiden, prothrombin, and methylene tetrahydrofolate reductase gene mutations did not seem to play a significant role in adverse pregnancy outcome in our population.

Prothrombin 20210G>A is an ancestral prothrombotic mutation that occurred in whites approximately 24 000 years ago

Prothrombin 20210G>A and factor V Leiden are common prothrombotic mutations in whites for which founder effects have been established. In this study, we analyzed the frequencies of 5 single nucleotide polymorphisms (SNPs) and 9 microsatellites flanking the prothrombin gene (F2) in 88 homozygotes for 20210A and 66 homozygotes for 20210G. For estimating the age of the prothrombin 20210G>A mutation, we used the DMLE+2.0 program, which analyzed linkage disequilibria between the mutation and the multiple markers that had been assessed. This analysis yielded an age estimate of 23 720 years (95% credible set, 19 080-31 340 years). A similar analysis by the DMLE+2.0 program was performed on 5 SNPs from previously studied homozygotes for factor V Leiden and controls that yielded an age estimate of 21 340 years (95% credible set, 16 880-29 480 years). The occurrence of the 2 mutations in whites toward the end of the last glaciation and their presently wide distribution in whites suggest selective evolutionary advantages for which some evidence was reported (diminished blood loss) or is controversial (protection against infections).

Varied Prevalence of Factor V G1691A (Leiden) and Prothrombin G20210A Single Nucleotide Polymorphisms Among Arabs

BACKGROUND

Factor V G1691A (FV-Leiden) and prothrombin (PRT) G20210A single nucleotide polymorphisms (SNPs) are major inherited risk factors of venous thromboembolism. In view of the heterogeneity in their world distribution and lack of sufficient information about their distribution among Arabs, we addressed the prevalence of both SNPs in 4 distinct Arab populations (Lebanon, Tunisia, Bahrain, and Saudi Arabia).

METHODS

Study subjects comprised 698 Lebanese, 313 Tunisian, 194 Bahraini, and 149 Saudi Arabian healthy subjects; genotyping was done by PCR-RFLP using Mnl I and Hind III for FV-Leiden and PRT G20210A, respectively.

RESULTS

The prevalence of the mutant A alleles of FV-Leiden and PRT G20210A were significantly higher among Lebanese (0.0788 and 0.0136) and Tunisians (0.0351 and 0.0128), as compared to Bahraini (0.0155 and 0.0052) and Saudi (0.0101 and 0.000) subjects. Higher frequency of the FV-Leiden G/A and A/A genotypes were seen in Lebanon (13.8 and 1.0%), followed by Tunisia (5.8 and 0.6%), Bahrain (3.1 and 0.0%) and Saudi Arabia ((2.0 and 0.0%). All PRT G20210A positive cases were in the heterozygote (G/A) state, and these comprised 3.6% for Lebanon, 2.6% for Tunisia, 1.0% for Bahrain. The carrier rate of FV-Leiden was significantly higher among Lebanese compared to the other populations (p < 0.001), while the difference in the prevalence of FV-Leiden between the other populations was not statistically different. With the exception of Lebanese-Saudi (p = 0.038), the prevalence of PRT G20210A was similar among the study communities. Furthermore, the overall average genetic differentiation between populations (estimated with the F(ST)) was 0.0022 for FV-Leiden and 0.005 for PRT G20210A.

CONCLUSIONS

These results further confirm the heterogeneity in FV-Leiden and PRT G20210A distribution among Arabs, and recommend potential institution of prophylactic measures for carriers of either or both SNPs.

Association between adverse pregnancy outcomes and maternal factor V G1691A (Leiden) and prothrombin G20210A genotypes in women with a history of recurrent idiopathic miscarriages

Thrombophilia was implicated in the development of pregnancy complications, including recurrent idiopathic pregnancy loss, and is aggravated in women who are carriers of factor V G1691A (FV Leiden) and prothrombin (PRT) G20210A single-nucleotide polymorphisms (SNPs). Previous studies examined the role of FV-Leiden and PRT G20210A in recurrent pregnancy loss with conflicting results. Here we examined the prevalence of FV Leiden and PRT G20210A SNPs, in 200 women with 3 or more consecutive early (n = 87), late (n = 41), or early-late (n = 72) recurrent pregnancy losses, and 200 age-matched fertile parous control women. APC resistance (APCR) was detected functionally (measuring the activated clotting time triggered by activated factor X in presence of a fixed amount of purified APC), and FV-Leiden and PRT G20210A genotypes were assessed by PCR. The frequency of the mutant FV (0.1400 vs. 0.0276; P < 0.001) but not PRT 20210 (0.0100 vs. 0.0225; P = 0.159) allele was higher in patients than controls, respectively. APC resistance with factor V Leiden was seen in 27% of patients compared to 11.5% of controls, while APC resistance without factor V Leiden was seen in 12.5% of patients compared to 9.5% of controls. Regression analysis demonstrated that the significant predictors for early abortion was FV Leiden; those for late abortion were oral contraceptive, APCR, and FV Leiden; and predictors for early-late abortions were oral contraceptives, obesity, FV Leiden, and smoking. APC resistance and FV Leiden, as well as combination of both, are common thrombotic defects seen in women with idiopathic recurrent pregnancy loss, thus testing for these is recommended in women who have experienced recurrent miscarriages.

Long-haul air travel before major surgery: a prescription for thromboembolism?

OBJECTIVE

To investigate the Incidence of postoperative venous thromboembolism (VTE) in patients who had flown long distances before major surgery.

PATIENTS AND METHODS

Using the Mayo Clinic computerized patient database, we Identified patients who had flown more than 5000 km before major surgery (travelers) and had experienced an episode of clinically significant VTE within 28 days after surgery. Individual medical records were reviewed for the diagnosis of VTE, pertinent risk factors, and outcome. We compared the Incidence of VTE in travelers to the incidence of VTE in patients from North America (nontravelers) undergoing similar surgical procedures.

RESULTS

Eleven patients met our criteria for long-haul air travel and clinically significant VTE within 28 days after surgery. Compared with nontravelers undergoing similar surgical procedures, long-haul travelers had a higher Incidence of VTE (4.9% vs 0.15%; P < .001). Compared with nontravelers who developed VTE, travelers were younger (P = .006), developed VTE earlier in the postoperative course (P = .01), had higher American Society of Anesthesiologists physical status classification (P = .02), and had higher prevalence of smoking (P = .007). Of the 11 travelers with VTE, 10 were of Middle Eastern origin.

CONCLUSION

Prolonged air travel before major surgery significantly increases the risk of perioperative VTE. Such patients should receive more Intensive VTE prophylactic measures during the flight and throughout the perioperative period.

A Case Control Study on the Contribution of Factor V-Leiden, Prothrombin G20210A, and MTHFR C677T Mutations to the Genetic Susceptibility of Deep Venous Thrombosis

BACKGROUND

Insofar as the inherited prothrombotic single nucleotide polymorphisms (SNPs) factor V G1691A (FV-Leiden), prothrombin (PRT) G20210A, and methylenetetrahydrofolate reductase (MTHFR), C677T are inherited risk factors of venous thromboembolism (VTE), the aim of this study was to determine the prevalence of single and combined SNPs in 198 patients with documented deep venous thrombosis (DVT), and 697 control subjects, and to estimate the associated risks.

METHODS

Factor V-Leiden, PRT G20210A, and MTHFR C677T were analyzed by PCR and restriction fragment length polymorphism (RFLP).

RESULTS

The prevalence of the heterozygote and homozygous variants for FV-Leiden (52.02 vs. 14.78%, RR 6.28), PRT G20210A (19.2 vs. 3.6%; RR 6.38), and to a lesser extent the T/T genotype of MTHFR C677T (20.71 vs. 11.0%; RR 1.49) were higher among DVT patients vs. controls, respectively. Two or more SNPs were detected in 90 of 198 patients (45.5%) and in 60 of 697 controls (8.6%), with odds ratios of 16.754 for joint occurrence of FV-Leiden and PRT G20210A, 10.471 for FV-Leiden and MTHFR C677T, and 6.283 for PRT G20210A SNPs and MTHFR 677T/T. Logistic regression analysis showed a further increased odds for FV-Leiden in combination with PRT G20210A (85.198) or homozygous MTHFR C677T (81.133), and to a lesser extent for PRT G20210A in combination with homozygous MTHFR C677T (20.812).

CONCLUSIONS

This indicates that FV-Leiden and PRT G20210A, more than MTHFR C677T, are important risk factors for DVT, and that the presence of more than one prothrombotic SNPs was associated with a significant risk of DVT.

Prevalence of Factor V Leiden and other thrombophilic traits among Cretan children with malignancy

BACKGROUND

The prevalence of thrombophilic traits, which might further enhance the risk of thrombotic complications in children treated for cancer, varies significantly among different populations.

OBJECTIVE

To evaluate the prevalence of common thrombophilic traits of the East Mediterranean Region, among native Cretan children treated for malignancy.

METHODS

Blood samples were consecutively collected from 31 native Cretan children treated for acute lymphoblastic leukaemia (n = 19) or other malignancies (n = 12) over 3 years. A molecular diagnosis based on the presence of Factor V Leiden (FVL), as well as on PT G20210A and MTHFR C677T mutation (in 14 patients) using PCR was applied. Patients who had central venous catheters (n = 29) were treated with an intensified thromboprophylaxis protocol that had been previously established in our institution.

RESULTS

The prevalence of the FVL mutation was 19.4% (95% CI = 5-32). The allele frequency is estimated at 11.3% (95% CI: 3.5-19.1) which is higher than that reported for the population of the mainland of Greece. The prevalence of the PT G20210A and MTHFR C677T mutation was 14.3 and 71.4%, respectively (corresponding allele frequencies 7.1 and 50%, respectively). Only one patient developed thrombosis, having although no thrombophilic trait.

CONCLUSIONS

Thrombophilic traits were relatively common in this group of native Cretan children treated for malignancy. Thromboprophylaxis should be considered in Cretan children in the presence of known acquired risk factors for thrombosis, but a larger prospective to study is first needed.

Prevalence of antiphospholipid antibodies, factor V G1691A (Leiden) and prothrombin G20210A mutations in early and late recurrent pregnancy loss

OBJECTIVE

We assessed the prevalence of inherited (FV-Leiden and PRT G20210A), and acquired (anti-PL antibodies) risk factors among habitual aborters in Tunisia.

STUDY DESIGN

We studied prospectively 146 patients with > or =3 consecutive early, late, or early-late recurrent pregnancy losses, together with 99 age-matched controls. Anticardiolipin antibodies (ACL), lupus anticoagulant (LA), and APC resistance (APCR) were detected by ELISA, dilute Russell Viper Venom Time (dRVVT), and coagulation tests, respectively, and FV-Leiden and PRT G20210A genotypes were assessed by PCR.

RESULTS

Anti-PL antibody frequencies were 45 and 9% among patients and controls, respectively (P < 0.001), with positive LA only (P = 0.004), or combined elevated ACL-positive LA being consistently higher (P < 0.001) among patients than controls. FV-Leiden (20.54% versus 6.06%), but not PRT G20210A (2.74% versus 4.04%) was significantly higher in patients versus controls. Among LA-positive cases higher prevalence of G/A (14/146 versus 1/99) and A/A genotypes (4/146 versus 0/99) were seen, and among ACL-positive cases higher prevalence of G/A (10/146 versus 0/99) and A/A genotypes (2/146 versus 0/99) were recorded.

CONCLUSIONS

Anti-PL antibodies and FV-Leiden, but not PRT G20210A, are associated with recurrent idiopathic pregnancy losses in Tunisian women.

Lupus anticoagulant, factor V Leiden, and methylenetetrahydrofolate reductase gene mutation in a lupus patient with cerebral venous thrombosis

We describe the case of a young Lebanese woman with systemic lupus erythematosus (SLE) and a positive lupus anticoagulant (LAC) who developed right internal jugular vein and sigmoid sinus thrombosis. Coagulation studies showed that in addition to the LAC the patient was heterozygous for the factor V (FV) Leiden mutation, and C677T mutation of the methylenetetrahydrofolate reductase gene. The high prevalence of FV Leiden in the eastern Mediterranean region suggests that we should probably screen our SLE patients in this area, especially those with anticardiolipin antibodies and/or LAC who have no history of thrombosis, for this and other thrombophilia markers. The detection of such abnormalities may have major practical consequences for the long-term management of these patients to prevent further thrombotic episodes.

Prevalence of factor V G1691A (factor V-Leiden) and prothrombin G20210A gene mutations in a recurrent miscarriage population

Factor V G1691A (FV-Leiden) and prothrombin G20210A mutations are major inherited risk factors for venous thrombosis. Recently, it was suggested that both mutations, through stimulation of venous and placental thrombosis events, were strongly associated with recurrent idiopathic miscarriages, although other studies disputed such a link. The aim of this study was to determine the prevalence of prothrombin G20210A and factor V G1691A (R506Q, FV-Leiden) mutations in women with recurrent idiopathic abortions and to recommend management for high-risk mutation carriers. One hundred ten women with two or more consecutive unexplained first-trimester miscarriages (mean age +/- SD, 32.3 +/- 5.3) were compared to 67 parous women with uncomplicated pregnancies (mean age +/- SD, 33.9 +/-7.3) (P = 0.134) from the same ethnic background. The presence or absence of the prothrombin G20210A and FV-Leiden mutations was assessed by PCR and RFLP analysis, using HindIII and MnlI digestion, respectively. In women with primary habitual abortion, 45 (40.91%) carried the FV-Leiden mutation, of whom 7 were in the homozygote and 38 were in the heterozygote states, and 15 (13.64%) carried the prothrombin G20210A mutation all as heterozygotes, compared to 16.42% and 2.99% carrier rates among controls, respectively, all of whom were heterozygote carriers. Of the other risk factors analyzed, smoking (OR 1.76; 95% CI = 0.79-3.94) was more prevalent in habitual aborters compared to controls. Both FV-Leiden and factor II G20210A mutations are major inherited risk factor associated with primary recurrent miscarriages. Women with a family or personal history of thrombosis should be screened before or early in the pregnancy for FV-Leiden and factor II G20210A mutations.

Factor V R506Q mutation-Leiden: an independent risk factor for venous thrombosis but not coronary artery disease

BACKGROUND

A specific point G-A transition at nucleotide position 1691 in the factor V (FV) gene, FV-Leiden, was associated with increased risk of venous thromboembolism (VTE). Insofar as the association of FV-Leiden with coronary artery disease (CAD) remains poorly defined, the aim of this study was to determine the prevalence of FV-Leiden in a sample of 68 VTE patients, 69 CAD patients, and 192 randomly selected healthy subjects.

METHODS

Total genomic DNA was extracted from the peripheral blood of study subjects and was used for PCR analysis. The presence (or absence) of FV-Leiden was assessed by PCR using primers flanking the mutant site (nt 1691), followed by hybridization with wild-type ('G') and mutant ('A') biotinylated DNA probes; detection was by DNA enzyme immunoassay (DEIA).

RESULTS

While the prevalence of FV-Leiden in CAD patients was not statistically different from that of healthy subjects (14.5 % vs. 15.1 %; P=0.890, odds ratio 0.95; 95 % confidence interval 0.43--2.06), a significant increase in FV-Leiden prevalence was seen in VTE patients (70.6 % in VTE patients; P<0.001, odds ratio 13.4, 95 % confidence interval 6.9--25.8). Of the 48 VTE patients who tested positive for FV-Leiden, 42 were heterozygotes (G/A), while 6 were homozygotes (A/A) (allele frequency 0.397). All 10 CAD patients positive for FV-Leiden were heterozygote carriers (allele frequency 0.072). While gender was not a factor in FV-Leiden expression, higher prevalence in FV-Leiden was seen in younger (< or =45 years) VTE patients (38/51 vs. 10/17).

CONCLUSION

FV-Leiden is a major inherited risk factor for VTE, with a peak incidence in younger patients, but does not appear to play any role in CAD pathogenesis in the population studied.