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

A universal diagnosis syntax

BACKGROUND

Diagnoses are crucial assets of clinical work and provide the foundation for treatment and follow up. They should be informative and customized to the patient's problem. Common prefixes, morphemes, and suffixes may aid the implementation of expressions that generate diagnoses.

RESULTS

Apt choices of symbols plays a major role in science. In this study, the variables e, o, and p are assigned to names of an etiological agent, a disorder, and a pathogenetic mechanism, respectively. The suffix -itis designates infections, allergies, inflammation, and/or immune reactions. Diagnoses (d) are generated by the formula d:= e&o&p where '&' means concatenation and ':= ' means assignment. Thus, with e:= 'Staphylococcus aureus ', o:= 'endocard', and p:= 'itis', d:= e&o&p generates the diagnosis d = 'Staphylococcus aureus endocarditis'. Diagnoses formed this way comply with common clinical diagnoses. Certain extensions generate complete, systematic medical diagnoses that are applicable to all medical specialties. For example, common medical prefixes, morphemes, and suffixes give rise to o = 'hypothyroidism', o = 'tachycardia', and o = 'hypophagocytosis'. The formula scales well with the developments in clinical medicine, systems biology, molecular biology, and microbiology. The diagnosis generating formula d:= e&o&p requires meticulous analysis of the components of diagnoses plus the introduction of appropriate variables and terms. Terms partition on established clinical categories and adhere to established clinical nomenclature. The syntax generates universal medical diagnoses.

CONCLUSIONS

The present study concerns a universal diagnosis syntax (UDS) that generates diagnoses using the formula d:= e&o&p with several extensions described in the study. The formula is easy to learn and covers diagnoses in all medical specialties. The present work succeeded in creating diagnoses from the formula. The fundamental insight is that no matter how complicated a diagnosis is it can be generated by a systematic process, which adds terms one by one. UDS may have implications for medical education and classifications. The formula lays a foundation for structured clinical decision-making. Formulas are hallmarks of hard science. So, d:= e&o&p anticipates a scientific medical revolution.

Detection of Exon 10 Mutation (rs6020) in Factor V Gene in Sudanese patients with Deep Vein Thrombosis.. [DOI: 10.21203/rs.3.rs-2500709/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: Deep vein thrombosis (DVT), a subgroup of venous thromboembolism (VTE), is one of the leading causes of morbidity and mortality globally, accounting for 60,000-100,000 fatalities per year. It affects around 0.1 percent of the population each year. In Sudanese patients with DVT, this study looked for probable harmful single nucleotide polymorphisms in exon 10 of the factor V gene. Method: Thirty blood samples were obtained from previously diagnosed DVT patients at Omdurman teaching hospital throughout the period of 16 August to 25 October 2018, as part of a descriptive cross-sectional research in Khartoum state. Exon 10 was amplified by PCR using sequence-specific primers after DNA was extracted using the guanidine chloride procedure. The fifteen best bands' PCR products were sequenced in both directions (BGI Company). Bioinformatics techniques were used to examine the sequences (Finch TV, BLAST, and Codon Code alignment). Result: The presence of a missense mutation (rs6020) in the factor V Leiden gene was discovered in 40% (6/15) of the patients in this investigation. In five cases, this mutation was heterozygous, whereas in one patient, it was homozygous. In the other nine cases, no mutations were found. Conclusion: rs6020 is more prevalent in the Sudanese population than other types of mutations. rs6020 polymorphism has a strong association with deep vein thrombosis in the Sudanese population. Further investigation of this mutation amongst larger Sudanese population is required in order to support this finding as well as to understand its clinical significance.

Large-scale screening for factor V Leiden (G1691A), prothrombin (G20210A), and MTHFR (C677T) mutations in Greek population

Background and aims

To provide a fair estimate of the prevalence of factor V Leiden (FVL) (G1691A), prothrombin (G20210A), and MTHFR (C677T) mutations in the Greek population.

Methods

We genotyped a representative sample of 974 apparently healthy Greek adults by the method of real‐time PCR and we calculated the allele frequencies of factor V Leiden (FVL) (G1691A), prothrombin (G20210A), and MTHFR (C677T) mutations. In addition, we determined the frequency of co‐occurrence of FVL (1691A) and prothrombin (20210A), FVL (1691A) and MTHFR (677T), prothrombin (20210A) and MTHFR (677T) mutations.

Results

Τhe career frequencies of FVL (1691A), prothrombin (20210A), and MTHFR (677T) alleles were 7.5%, 4.5%, and 49.3% while the allele frequencies were 4%, 2.25%, and 39.5%, respectively. The coexistence of the allele frequencies combinations of two, FVL (1691A) and Prothrombin (20210A), FVL (1691A) and MTHFR (677T), prothrombin (20210A) and MTHFR (677T) was found in 1 (0.9%), 29 (3.5%), and 22 (3%) samples, respectively. Triple heterozygous carriers were not found.

Conclusion

Allele frequencies of the two (FVL and MTHFR) mutations are higher compared with published data. The large sample size of our study enhances the validity of our results and suggests a biological affinity of Greek population with Southern Italian populations.

Osteonecrosis of the Jaws in Patients with Hereditary Thrombophilia/Hypofibrinolysis-From Pathophysiology to Therapeutic Implications

Osteonecrosis of the jaws (ONJ) usually has a clear etiology. Local infection or trauma, radiotherapy and drugs that disrupt the vascular supply or bone turnover in the jaws are its major contributors. The thrombotic occlusion of the bone’s venous outflow that occurs in individuals with hereditary thrombophilia and/or hypofibrinolysis has a less known impact on jaw health and healing capability. Our research provides the most comprehensive, up-to-date and systematized information on the prevalence and significance of hereditary thrombophilia and/or hypofibrinolysis states in ONJ. We found that hereditary prothrombotic abnormalities are common in patients with ONJ refractory to conventional medical and dental treatments. Thrombophilia traits usually coexist with hypofibrinolysis traits. We also found that frequently acquired prothrombotic abnormalities coexist with hereditary ones and enhance their negative effect on the bone. Therefore, we recommend a personalized therapeutic approach that addresses, in particular, the modifiable risk factors of ONJ. Patients will have clear benefits, as they will be relieved of persistent pain and repeated dental procedures.

Osteonecrosis of the Femoral Head in Patients with Hypercoagulability-From Pathophysiology to Therapeutic Implications

Osteonecrosis of the femoral head (ONFH) is a debilitating disease with major social and economic impacts. It frequently affects relatively young adults and has a predilection for rapid progression to femoral head collapse and end-stage hip arthritis. If not diagnosed and treated properly in the early stages, ONFH has devastating consequences and leads to mandatory total hip arthroplasty. The pathophysiology of non-traumatic ONFH is very complex and not fully understood. While multiple risk factors have been associated with secondary ONFH, there are still many cases in which a clear etiology cannot be established. Recognition of the prothrombotic state as part of the etiopathogeny of primary ONFH provides an opportunity for early medical intervention, with implications for both prophylaxis and therapy aimed at slowing or stopping the progression of the disease. Hereditary thrombophilia and hypofibrinolysis are associated with thrombotic occlusion of bone vessels. Anticoagulant treatment can change the natural course of the disease and improve patients' quality of life. The present work focused on highlighting the association between hereditary thrombophilia/hypofibrinolysis states and ONFH, emphasizing the importance of identifying this condition. We have also provided strong arguments to support the efficiency and safety of anticoagulant treatment in the early stages of the disease, encouraging etiological diagnosis and prompt therapeutic intervention. In the era of direct oral anticoagulants, new therapeutic options have become available, enabling better long-term compliance.

Pregnancy associated coagulopathies in selected community hospitals in Southwest Nigeria

Background and Aim:

Pregnancy is characterized by multiple changes in the coagulation system which occurs at different stages of the condition, representing one of the major triggers of maternal and foetal morbidity/mortality in the world during complicated incidences. This study determined the prevalence of coagulation disorders among pregnant women in Southwest Nigeria to buttress the need for prompt and accurate routine diagnosis of these disorders.

Methods:

Four hundred and five participants (405) attending some selected tertiary health facilities in Southwestern Nigeria were randomly recruited for the study, comprising two hundred and seventy (270) pregnant subjects and one hundred and thirty-five (135) apparently healthy age- and socio-economic status-matched non-pregnant women as controls. The platelet count was assessed; prothrombin time and activated partial thromboplastin time were assessed. Immunoturbidimetric and chromogenic techniques were also used to assess the level of D-dimer and activated protein C resistance.

Results:

Platelet count, PT and INR in all three trimesters were significantly (p < 0.05) reduced when compared to the non-pregnant control subjects. However, the level of circulating D-dimer was significantly (p < 0.05) increased in all three trimesters when compared with the control group, with observable steady increase in the second and third trimesters. Also, 13% of respondents had thrombotic predisposition and 14.8% with tendencies for consumption coagulopathy while 1.1% are APCr positive individuals.

Conclusion:

The study affirms the hypercoagulable state of pregnancy coupled with mild gestational thrombocytopenia which could be pointers to onset of coagulation disorders in some participants, subjects with coagulation profiles indicative of thrombotic tendencies and possible onset of consumption coagulopathy and the presence of activated protein C resistant in the region. A review of the coagulation monitoring strategies for pregnant women from primary care to include more definite assays and its proper implementation will immensely contribute to early diagnosis along with intervention for pregnancy associated coagulopathies in resource-limited settings.

Coagulation F13A1 V34L, fibrinogen and homocysteine versus conventional risk factors in the pathogenesis of MI in young persons

BACKGROUND

The pathogenesis of myocardial infarction (MI) involves environmental and genetic risk factors, with the latter putatively playing significant roles in younger patients. Genetic variability in coagulation factors comprises one such group. The coagulation factor 13 subunit A (F13A1) Val34Leu polymorphism (rs5985) has yielded variable findings in literature, with no prior South Asian data.

METHODS

We studied the frequency of this polymorphism using the amplification-created restriction-enzyme site (ACRES) polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 101 MI patients aged below 40 years and 103 controls along with plasma fibrinogen and serum homocysteine levels.

RESULTS

The distribution of Val/Val, Val/Leu and Leu/Leu genotypes was similar among cases (72.3%, 26.7% and 1.0%) and controls (78.6%, 19.4% and 1.9%, respectively). Val and Leu allele frequencies were 85.6% and 14.4% among patients and 88.3% and 11.7% among controls, respectively (p = .416). Mean plasma fibrinogen was higher in patients vis-à-vis controls (3.1 versus 3.7 g/l; p < .001) but homocysteine was elevated in both patients (52%) and controls (67%) (p = .225). Multivariate analysis revealed hypertension (p < .001, OR 6.16) and smoking (p < .001, OR 5.48) to impart strongest risk followed by positive family history, plasma fibrinogen levels and male gender.

CONCLUSIONS

Despite its small sample size, this first South Asian study suggests neither protective nor deleterious effects of the F13A1 Val34Leu polymorphism on the risk of MI in young persons. The Leu allele frequency is intermediate to that reported from the West and the Far East. Traditional risk factors contribute greatly to risk even in younger MI patients in South Asia.

Pharmacogenomic survey of Qatari populations using whole-genome and exome sequences

The Arabs represent one of the most genetically heterogeneous populations characterized by a high prevalence of Mendelian disorders due to consanguinity. Population-scale genomic datasets provide a unique opportunity to understand the epidemiology of variants associated with differential therapeutic response. We analyzed publicly available genomic data for 1005 Qatari individuals encompassing five subpopulations. The frequencies of known and novel pharmacogenetic variants were compared with global populations. Impact of genetic substructure on the pharmacogenetic landscape of the population was studied. We report an average of three clinically actionable pharmacogenetic variants with FDA-recommended genetic testing per Qatari individual regardless of their genetic ancestry. We observed extensive differences in the frequencies of clinically actionable pharmacogenetic variants among the Qatari subpopulations. Our analysis revealed 3579 deleterious pharmacogenetic variants potentially altering the function of 1163 genes associated with 1565 drugs. This study has thus compiled the first comprehensive landscape of pharmacogenetic variants for any Arab population.

Laboratory assessment of Activated Protein C Resistance/Factor V-Leiden and performance characteristics of a new quantitative assay

Activated Protein C Resistance is mainly associated to a factor V mutation (RQ506), which induces a deficient inactivation of activated factor V by activated protein C, and is associated to an increased risk of venous and arterial thrombosis in affected individuals, caused by the prolonged activated factor V survival. Its prevalence is mainly in Caucasians (about 5%), and this mutation is absent in Africans and Asians. Presence of Factor V-Leiden is usually evidenced with clotting methods, using a two-step APTT assay performed without or with APC: prolongation of blood coagulation time is decreased if this factor is present. The R506Q Factor V-Leiden mutation is now usually characterized using molecular biology, and this technique tends to become the first intention assay for characterization of patients. Both techniques are qualitative, and allow classifying tested individuals as heterozygotes or homozygotes for the mutation, when present. A new quantitative assay for Factor V-Leiden, using a one-step clotting method, has been developed, and designed with highly purified human coagulation proteins. Clotting is triggered with human Factor Xa, in presence of calcium and phospholipids (mixture which favours APC action over clotting process). Diluted tested plasma, is supplemented with a clotting mixture containing human fibrinogen, prothrombin, and protein S at a constant concentration. APC is added, and clotting is initiated with calcium. Calibration is performed with a pool of plasmas from patients carrying the R506Q Factor V mutation, and its mixtures with normal plasma. Homozygous patients have clotting times of about <40sec; heterozygous patients have clotting times of about 40-60sec and normal individuals yield clotting times >70sec. Factor V-Leiden concentration is usually >75% in homozygous patients, 30-60% in heterozygous patients and below 5% in normal. The assay is insensitive to clotting factor deficiencies (II, VII, VIII: C, IX, X), dicoumarol or heparin therapies, and has no interference with lupus anticoagulant (LA). This new assay for Factor V-Leiden can be easily used in any coagulation laboratory, is performed as a single test, and is quantitative. This assay has a high robustness, is accurate and presents a good intra- (<3%) and inter-assay (<5%) variability. It contributes solving most of the laboratory issues faced when testing factor V-Leiden. Quantitation of Factor V-L could contribute to a better assessment of thrombotic risk in affected patients, as this complication is first associated to and caused by the presence of a defined amount of FVa.

Thrombophilia genetic testing in Romanian young women with acute thrombotic events: role of Factor V Leiden, Prothrombin G20210A, MTHFR C677T and A1298C polymorphisms / Evaluarea genetică a trombofiliilor la femei tinere din România cu evenimente acute trombotice: rolul Factorului V Leiden, Protrombinei G20210A, polimorfismelor MTHFR C677T și A1298C

Objective: The present case-control study aimed at evaluating the contribution of thrombophilic polymorphisms to acute venous (VTE) as well as arterial thrombotic events (ATE) in a population of young women with few traditional thrombotic factors (CVRF).

Methods: We consecutively enrolled patients under 45 years of age, with less than 3 CVRF, evaluated for VTE or ATE, women and men as a comparator. The control group consisted of healthy young women. A thrombophilia panel and genetic testing for Factor V Leiden (FVL), G20210A Prothrombin and MTHFR polimorphisms were done.

Results: A total of 323 persons were enrolled: 71 women and 121 men with thromboembolic events, and 131 healthy female as controls. Hyperhomocysteinemia was more frequent in ATE (30.4%) than VTE female patients (6.25%), p<0.01. Genetic testing was available in 45 women and 84 men with acute thrombotic events and in all controls. Homozygous FVL was associated with VTE in young women (10.3% vs 0% controls, p<0.01). Prothrombin G20210A polymorphism had the lowest prevalence – 5.4% and only heterozygosity was found. MTHFR C677T heterozygosity showed no significant difference between women patients and controls (62.2 % vs 43.5% respectively, p=0.1). The homozygous status, less frequent (6.6%), was not associated with ATE or VTE. Homozygous MTHFR A1298C was associated with VTE in women (17.2% patients vs 4.5% controls, OR 4.34, p 0.02, CI 1.22-15.3).

Conclusion: In young women with few CVRF, mild hyperhomocysteinemia, homozygosity for FVL and for MTHFR A1298C polymorphisms increase the risk for VTE but not ATE. MTHFR polymorphisms are found with increased frequency in both healthy persons and patients therefore, their significance as an important thrombotic risk modifier remains unclear.

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.

Genetic Risk Factors in Venous Thromboembolism

Genetic risk factors predispose to thrombophilia and play the most important etiopathogenic role in venous thromboembolism (VTE) in people younger than 50 years old. At least one inherited risk factor could be found in about half of the cases with a first episode of idiopathic VTE.Roughly, genetic risk factors are classified into two main categories: loss of function mutations (such as deficiencies of antithrombin, protein C, protein S) and gain of function mutations, (such as prothrombin mutation G20210A, factor V Leiden). A revolutionary contribution to the genetic background of VTE was brought by the achievements of the genome-wide association studies which analyze the association of a huge number of polymorphisms in large sample size.Hereditary thrombophilia testing should be done only in selected cases. The detection of hereditary thrombophilia has impact on the management of the anticoagulation in children with purpura fulminans, pregnant women at risk of VTE and may be useful in the assessment of the risk for recurrent thrombosis in patients presenting an episode of VTE at a young age (<40 years) and in cases with positive family history regarding thrombosis.

The prevalence of Factor V Leiden, prothrombin G20210A, MTHFR C677T and MTHFR A1298C mutations in healthy Turkish population

BACKGROUND

Factor V Leiden (FVL), prothrombin gene (PT G20210A) and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms are the main biomarkers used in the evaluation of tendency to venous thromboembolism. Our study aimed to investigate the distribution frequencies of these polymorphisms in healthy Turks living in the urban Yozgat region. 

MATERIAL AND METHODS

This study included 90 blood donor candidates. All the donors were apparently healthy, and there was no family relationship between them. Mutations including FVL, PT G20210A, and MTHFR (C677T, A1298C) were investigated in all participants. Screening of polymorphisms was carried out using the SNaPshot® multiplex system.

RESULTS

There were 42 male and 48 female individuals with age range 17-78 years and mean age 47.5 ± 13.6 years. The heterozygous FVL mutation was noted in 17 (10 male and seven female) donors (19%). FVL mutation was more frequently encountered in males than in females (23.8% vs. 12.5%). The heterozygous PT G20210A mutation was observed in five (5.5%) of the 90 (three male, two female) donors. The prevalence of homozygous polymorphisms of MTHFR C677T was 8.8% and of MTHFR A1298C 13.3%. On the other hand, four of the 90 participants (4.4%) carried none of these polymorphisms.

CONCLUSION

This study showed that the prevalence of FVL, PT G20210A, MTHFR C677T and MTHFR A1298C polymorphisms is quite high, and the coexistence of FVL with other genotypes is not rare in a healthy Turkish population living in the Yozgat region. Of course, further detailed studies should be performed to support these findings. Hippokratia 2015; 19 (4): 309-313.

The Contributions of Thrombophilic Mutations to Genetic Susceptibility to Deep Venous Thrombosis in Iraqi Patients

BACKGROUND AND AIMS

There is a paucity of data on the contribution of various thrombophilic mutations to the development of venous thrombosis in Iraqi patients. Therefore we designed a study to assess the frequencies of known thrombophilic mutations in this population.

METHODS

100 consecutive Iraqi patients with color Doppler confirmed deep venous thrombosis of the lower extremities and 100 age- and sex-matched healthy controls were enrolled in the study. Their DNAs were tested by multiplex polymerase chain reaction (PCR) followed by reverse hybridization for factor V Leiden (FVL), the prothrombin (PT) G20210A SNP, and the MTHFR C677T SNP. The factor V A4070G mutation was assessed by restriction fragment length polymorphism-PCR.

RESULTS

The prevalence of FVL was 13% in patients versus 2% in controls (odd ratios [OR] 7.3; p=0.007). Patients with recurrent thrombosis also had a significantly higher frequency of Factor V Leiden (OR 8.4, p=0.0007). The prothrombin G20210A, SNP, the factor V A4070G SNP, and the MTHFR 677 TT genotypes were present among patients at 5%, 9%, and 11%, respectively, and among controls at 2%, 6%, and 6%; none of these single mutation prevalence differences were significant. Interestingly, however, when these polymorphisms were studied in aggregate we found that 24% of patients had two or more thrombophilic alleles, compared to only 8% of the controls (OR 3.6; p=0.002). This subgroup included significantly more patients with proximal (p=0.007) and recurrent thrombosis (p=0.012), as well as younger patients (≤40 years) (p=0.026).

CONCLUSION

Two or more thrombophilic alleles, as well as FVL on its own, were both significantly associated with an increased risk of venous thrombosis and recurrence in Iraqi patients. Single thrombophilic mutations on their own were not associated with an increased risk.

Risk of Budd-Chiari syndrome associated with factor V Leiden and G20210A prothrombin mutation: a meta-analysis

Background

Various studies have demonstrated that factor V Leiden (FVL) and G20210A prothrombin mutation contribute to the risk of Budd-Chiari syndrome (BCS), while other studies provided conflicting findings. In order to derive more precise estimations of the relationships, a meta-analysis was performed.

Methods

Eligible articles were identified through search of databases including Pubmed, Chinese Biomedical Database (CBM, Chinese), and Chinese National Knowledge Infrastructure (CNKI, Chinese). Odd ratios (ORs) with 95% confidence intervals (CIs) were calculated using random- or fixed- model.

Results

Finally, twelve studies were included for FVL and nine studies were included for G20210A prothrombin mutation. With respect to FVL, significantly increased BCS risk was found in the overall population (OR = 6.29, 95%CI = 4.23–9.36). Subgroup analyses suggested that FVL was associated with an increased risk of BCS in the population with high background mutation prevalence (>1% in the normal population). No significant association was found between BCS and G20210A prothrombin mutation (OR = 1.78, 95%CI = 0.77–4.11).

Conclusion

The presence of FVL should be evaluated in patients with BCS. Conversely, G20210A prothrombin mutation is not significantly associated with risk of BCS. Large-scale well designed studies are necessary to be conducted to further confirm or refute the observed association.

Association of allelic variants of factor V Leiden, prothrombin and methylenetetrahydrofolate reductase with thrombosis or ocular involvement in Behçet's disease: a systematic review and meta-analysis

Thrombosis is frequent in patients with Behçet's disease (BD), although the exact cause remains uncertain. Some single nucleotide polymorphism (SNP) (G1691A in factor V gene, also called factor V Leiden [FVL], G20210A in prothrombin gene and C677T in methyltetrahydrofolate reductase [MTHFR] gene) have been associated with thrombosis and ocular involvement in BD with controversial results.

AIM

To assess the effects of FVL, prothrombin and MTHFR SNP variants in patients with BD and thrombosis and ocular involvement by means of a systematic review and meta-analysis.

METHODS

We retrieved studies analyzing the genotype of the above-mentioned polymorphism among patients with BD. A meta-analysis was conducted in a random effects model and calculations of odds ratio (OR) and confidence intervals (CI) were done. Sensitivity analysis and tests for heterogeneity of the results were performed.

RESULTS

27 previous studies analyzed the association of BD and thrombosis with the FVL, prothrombin and MTHFR polymorphisms. A significant association was found between the possession of the AA or GA genotypes of FVL polymorphism among patients with BD and the presence of any thrombosis (OR=2.51; 95% CI: 1.68, 3.74; P<0.00001). In addition, a significant association was found between the possession of the GA or AA genotypes and the presence of BD (OR=2.67; 95% CI: 1.93. 3.72; P<0.00001) when cases with BD and healthy controls were compared. This association was not found when studies from Turkey were excluded. No association was found between prothrombin and MTHFR SNPs and thrombosis in BD, and no association between any SNP and ocular involvement was shown either.

CONCLUSIONS

Factor V Leiden could be responsible for some thrombotic events in at least Turkish patients. However, this relationship has to be demonstrated from a pathogenic point of view.

Causes of adult splanchnic vein thrombosis in the mediterranean area

The term splanchnic vein thrombosis encompasses Budd-Chiari syndrome (BCS), extrahepatic portal vein obstruction (EHPVO), and mesenteric vein thrombosis.

Risk factors can be local or systemic. A local precipitating factor is rare in BCS, while it is common in patients with portal vein thrombosis. Chronic myeloproliferative neoplasms (MPN) are the leading systemic cause of splanchnic vein thrombosis, and are diagnosed in half BCS patients and one-third of EHPVO patients; the somatic mutation JAK2 V617F is detectable in a large majority of patients with overt MPN, and up to 40% of patients without overt MPN. Inherited thrombophilia is present in at least one-third of patients, and the factor V Leiden or the prothrombin G20210A mutations are the most common mutations found in BCS or EHPVO patients, respectively. Multiple factors are present in approximately one-third of patients with BCS and two- thirds of patients with portal vein thrombosis.

In a few patient series from the Southern Mediterranean area the high prevalence of MPN and thrombophilia as underlying cause of BCS is confirmed, although the data should be considered preliminary. Peculiar risk factors present in the area are Behçet’s disease and hydatidosis; moreover, membraneous webs, typically found in Asian patients, are present in a significant portion of cases.