Distinct association of factor V-Leiden and prothrombin G20210A mutations with deep venous thrombosis in Tunisia and Lebanon

Association of venous thromboembolism and myocardial infarction with Factor V Leiden and Factor II gene mutations among Libyan patients

Factor V Leiden G1691A (FVL) and Factor II prothrombin G20210A (PGM) mutations are the leading causes of thrombophilia. In this study, we have investigated the prevalence of the FVL G1691A and PGM G20210A single nucleotide polymorphisms (SNPs) among Libyan deep vein thrombosis (DVT) and myocardial infarction (MI) patients. SNP genotyping was performed using high-resolution melt analysis (HRM) and DNA sequencing. Biochemical parameters conducted on 112 males and 93 females showed no significant difference in means between the control group and the deep vein thrombosis and myocardial infarction groups. For Factor V Leiden, 40 samples were genotyped. Of the 40 samples, 6 (15.0%) of them were heterozygous and no one was homozygous. As for Factor II SNP, 59 samples were genotyped and only 2 (3.3%) were heterozygous. All the heterozygous samples showed 100% concordance between the HRM-PCR and DNA sequence analysis. Our study showed, for the first time, that both the FVL and PGM mutations are present among Libyan DVT and MI patients and that the FVL mutation is significantly associated with DVT but not with MI. However, our results do not support the association of PGM G20210A mutation with DVT or MI.

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.

Etiology of Recurrent Pregnancy Loss in Saudi Females

Objective:

The aim of our retrospective study was to assess the etiology of recurrent pregnancy loss (RPL) in Saudi couples attending a specialized RPL clinic at King Fahad Hospital of the University, Al-Khobar, Saudi Arabia.

Patients and Methods:

A total of 59 couples attending the RPL clinic between January 2010 and December 2013 and who had completed their workup and investigations for RPL were included in the study. Data were collected from patients’ charts and computer-based laboratory results.

Results:

Protein S deficiency was found in 47% of patients, a chromosomal abnormality in 6.7%, uterine abnormality in 12%, antiphospholipid syndrome (APS) in 12%, and antithrombin III and Protein C deficiency in 1.7%. However, no patient had Factor V Leiden mutation. In 39% of the patients, there was no identifiable cause, and therefore, they had been diagnosed as unexplained RPL.

Conclusion:

The most common cause of RPL was Protein S deficiency followed by congenital uterine anomalies and APS. Almost 40% of couples with RPL remain with unknown etiology.

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.

Association Between the G20210A Polymorphism of Prothrombin Gene and Myocardial Infarction in Tunisian Population

The prothrombin is the precursor of the serine protease thrombin, a key enzyme in homeostasis. Prothrombin G20210A polymorphism (rs1799963) was described as a moderate risk factor for venous thrombosis because this mutation is associated with prothrombin elevated levels which may lead to an imbalance between the procoagulant, anticoagulant, and fibrinolytic system. 20210A carriers have an increased risk of thrombosis. In this study, we proposed to determine the prevalence of 20210A prothrombin variant among Tunisian population, and to evaluate the potential relevance of this variant with myocardial infarction. This study included 1290 unrelated Tunisians (1007 male and 283 female) divided in two groups: Four hundred and eighty-seven MI patients (mean age: 52.64 ± 8.98 years) and 803 apparently healthy controls (mean age: 51 ± 8.99). The prothrombin G20210A polymorphism was carried out by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) analysis. The distribution of genotypes was in accordance with Hardy-Weinberg equilibrium (p > 0.05). A significant difference in genotype distribution and allele frequency was observed between patients and controls. Male patients with MI had a frequency of 97 % for GG genotype and 3 % for GA+AA genotypes. The control group had a frequency of 99 % for the GG genotype and 1 % for the GA+AA genotypes which is significantly lower than the frequency found in patients (p = 0.01). The same genotype frequencies were found in women (p = 0.032). The MI patient group showed a significantly higher frequency of 20210A allele compared to controls 0.02 versus 0.01 [OR = 3.60 (95 % CI = 1.29-10.53), p = 0.005] in men and 0.015 versus 0.068 [OR = 4.68 (95 % CI = 1.60-14.26), p = 0.001] in women. Our work showed a significant but not independent association between the G20210A polymorphism of the prothrombin gene and MI in the Tunisian population.

Polymorphisms in thrombophilic genes are associated with deep venous thromboembolism in an Iranian population

It has been revealed that the inherited thrombophilia increases the risk of thrombosis in the venous system. To study the association of factor V G1691A, factor V HR2 (4070A/G), prothrombin G20210A, and PAI-1 (- 675 I/D, 5G/4G) polymorphisms with deep venous thromboembolism (DVT), these polymorphisms were investigated. A total of 193 patients who presented clinical symptoms of deep venous thromboembolism including 103 men and 90 women, and 500 healthy individuals without both personal and family histories of thromboembolic disorders including 275 men and 225 women were recruited into the study. Genotyping was carried out using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) technique. Our results showed that the genotype distribution for FV (G1691A and A4070G) and PAI-1 4G/5G polymorphisms in DVT patients were significantly higher than healthy control (P < 0.05). Also, the mutant allele frequencies for all studied polymorphisms differed significantly between the case and control groups (P < 0.05). We concluded that the prevalence of FV (G1691A and A4070G) and PAI-1 4G/5G polymorphisms increased the risk of DVT occurrence in subjects. These findings provide additional evidence to support the hypothesis that thrombophilic gene polymorphisms are involved in vascular thromboembolism.

Thrombophilic risk factors in different types of retinal vein occlusion in Tunisian patients

BACKGROUND

Retinal vein occlusion (RVO) is the second most common cause of vision loss because of retinal vascular disease. There are 2 types of RVO: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). The pathogenesis of RVO is multifactorial. The role of factor V Leiden (FVL) and prothrombin mutations was examined in patients with CRVO and BRVO.

METHODS

FVL and prothrombin were investigated by extracting DNA of 88 patients with RVO. Sixteen of the patients were diagnosed with CRVO, 4 with hemispheric retinal vein occlusion, and 68 with BRVO. The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Significant differences were found in the frequencies of the genotypes for both the FVL (G1691A) (P<10(-3), odds ratio [OR]=17.4, confidence interval [CI]=6.20-59) and prothrombin (G20210A) (P=.007, OR=5.11, CI=1.30-29) polymorphisms between RVO patients and healthy controls. Additionally, the frequency of the GA genotype for the G1691A polymorphism was significantly higher among the patients in a subset of BRVO compared with controls (P<10(-3), OR=21.4, CI=7.34-74.2). However, no statistically significant differences were found in the frequencies of the prothrombin G20210A polymorphism between the BRVO group and healthy controls (P=.09, OR=3.13, CI=64-19.9). The frequency of both G1691A and G20210A genotypes among the patients of a CRVO subgroup was significantly higher compared with controls (P<10(-3), OR=11.4, CI=2.94-44.2; P=.007, OR=10.8, CI=2.15-54.1, respectively), suggesting an association between these polymorphisms and CRVO.

CONCLUSIONS

Large study would be required to understand completely the contribution of these markers in the risk of all types of RVO.

Risk of venous thromboembolism associated with single and combined effects of Factor V Leiden, Prothrombin 20210A and Methylenetethraydrofolate reductase C677T: a meta-analysis involving over 11,000 cases and 21,000 controls

Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden, FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95 % confidence intervals [CI]: 0.98-1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR = 4.22; 95 % CI: 3.35-5.32; and OR = 2.79;95 % CI: 2.25-3.46, respectively), in double heterozygotes (OR = 3.42; 95 %CI 1.64-7.13), and in homozygous FVL or PT20210A (OR = 11.45; 95 %CI: 6.79-19.29; and OR: 6.74 (CI 95 % 2.19-20.72), respectively). The stratified analyses showed a stronger effect of FVL on individuals ≤ 45 years (p value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought.

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.

Epidemiology of Prothrombin G20210A Mutation in the Mediterranean Region

There are many genetic and acquired risk factors that are known to cause venous thromboembolic disorders (VTE). One of these is the Prothrombin G20210A mutation, which has been identified in 1996. Prothrombin G20210A mutation causes higher levels of the clotting factor prothrombin in the blood of carriers, which creates a higher tendency towards blood clotting (hypercoagulability), and therefore the carriers become at higher risk of developing VTE. High prevalence of Prothrombin G20210A mutation was reported in Caucasian populations, but the prevalence was almost absent in non-Caucasians. That was most obvious in countries of South Europe and the Mediterranean region. This review article discusses Prothrombin G20210A mutation, how it causes VTE, the origin of the mutation, and its distribution worldwide with special concentration on the Mediterranean area.

Prevalence of factor V Leiden in south Tunisian blood donors

Venous thrombosis (VT) is a common disease with multifactorial pathogenesis. Factor V Leiden mutation (G1691A) (FVL) is the most common risk factor in venous thrombosis. The prevalence of FVL varies according to geography and ethnicity. Hence, in several countries there is a difference in the frequency of this mutation between the southern, central and north. In Tunisia, no data is available about prevalence of FVL mutation by geographical origin. For this reason, we sought the prevalence of FVL mutation in blood donor of south Tunisia population. FVL has been detected by APCR-test and confirmed by PCR-RFLP and sequencing. Two hundred fifty blood donors, different in age and sex were included in this study to determine the prevalence of FVL in blood donors. FVL mutation was found in 13.6% of the studied population. Thirty-one were heterozygous and three persons were homozygous with a rate of 12.4 and 1.2%, respectively. In conclusion, FVL mutation is very common in south Tunisian population.

Epidemiology of activated protein C resistance and factor v leiden mutation in the mediterranean region

Venous thromboembolic disorders (VTE) are serious disorders with high morbidity and mortality rates. Many genetic and acquired risk factors were identified to cause VTE. The most common genetic risk factor is Factor V Leiden mutation (FVL). FVL was found in high percentage of populations of Caucasian origin but was almost absent in non-Caucasians. It was also reported in populations living in North Africa and the Middle East. This review article briefly explains FVL and how it causes VTE, the distribution of FVL worldwide, and then it elaborates on the epidemiology of FVL in the Mediterranean Region and how this brought speculations that FVL might have originated in the Eastern Mediterranean area.

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.

A case control study of deep venous thrombosis in relation to factor V G1691A (Leiden) and A4070G (HR2 Haplotype) polymorphisms

Activated protein C resistance (APCR) is a significant risk factor for venous thromboembolism (VTE), with the factor V (FV) G1691A (Leiden) mutation accounting for the majority of inherited APCR cases. An additional FV polymorphism, A4074G (FV-HR2), reportedly increased VTE risk by some, but not all groups. We determined the prevalence of FV-Leiden and FV-HR2 SNPs in 126 patients with deep venous thrombosis (DVT), and 197 control subjects. Frequencies of FV-Leiden A and HR2 G alleles, together with FV-Leiden G/A and A/A (but not HR2 A/G) genotypes were significantly higher among patients. While no significant linkage disequilibrium was noted between FV 1691A and 4070G or A alleles, significantly higher prevalence of single-mutant 1691G/4070G and 1691A/4070A haplotypes were seen in patients. FV Leiden and FV HR2 haplotype are independent risk factors for DVT, and their coinheritance does not seem to increase significantly DVT risk imparted by either.