G-455A polymorphism of beta-fibrinogen gene and the risk of premature myocardial infarction in Greece

Genetic polymorphisms in early-onset myocardial infarction in a sample of Iraqi patients: a pilot study

OBJECTIVES

Early-onset myocardial infarction constitutes nearly one third of cases of myocardial infarction among Iraqis, which is rather higher than the proportions reported in many Western countries. Thus this study was initiated to investigate the role of some genetic polymorphisms, as well as acquired risk factors in this condition.

RESULTS

A total of 102 Iraqi patients with first myocardial infarction aged 50 years, and 77 matched controls were enrolled. The DNAs of participants were screened for nine polymorphisms, namely: β-Fibrinogen (- 455G > A), Factor XIII (V34L), Plasminogen Activator inhibitor-1 (PAI-1, 4G/5G), Human Platelet Antigen-1 (HPA1a/b), 5,10-Methylenetetrahydrofolate Reductase MTHFR (C677T) and MTHFR (A1298C), Angiotensin-Converting Enzyme (ACE) 287 bp insertion/deletion (I/D), Apolipoprotein-B (ApoB: R3500Q), and Apolipoprotein-E (Apo E: E2/E3/E4), using PCR and reverse hybridization technique. Among traditional risk factors, univariate analysis revealed that smoking (OR 2.86 [95%CI 1.53-5.34]), hyperlipidemia (OR 5.23 [95%CI 2.66-10.29]), and diabetes mellitus (OR 4.05 [95% CI 1.57-10.41]) were significantly higher among patients compared to controls (P<0.001, <0.001 and 0.002 respectively), while none of the nine genetic polymorphisms reached significance. Multivariate Logistic regression, however, revealed that only smoking and hyperlipidemia retained significance (P of < 0.001 each). The need to initiate further studies on larger cohorts is paramount to understand the higher than expected frequency of early-onset myocardial infarction in our population.

Evaluation of single nucleotide polymorphisms in 6 candidate genes and carotid intima-media thickness in community-dwelling residents

Evidence suggests the existence of association between a large panel of modifiable biomarkers representing inflammation, coagulation, paraoxonase, and endothelial activation pathways and carotid atherosclerosis. Thus, this study investigated whether CRP, FGA, FGB, FGG, PON1, and EDNRA gene variants affected plasma hs-CRP, fibrinogen levels, and thickness of carotid intima media thickness (IMT). Nineteen single-nucleotide polymorphisms of CRP, FGA, FGB, FGG, PON1, and EDNRA genes were examined in 480 participants from 160 families. Carotid IMT was measured by ultrasound. Generalized linear models with generalized estimating equation were utilized to consider the dependence of subjects within families. In the recessive model, homozygotes for the minor alleles of rs1800789, rs1800790 and rs4220 SNPs in FGB gene indicated a reduced risk of IMT (Exp. β = 0.89, 0.89, 0.88), which remained significant after adjustment for confounding factors. Significant interaction effects between CRP SNP rs1130864 and rs3093059 and gender for IMT were observed with a significant association in men only. Men carrying minor-minor genotype of CRP SNP rs1130864 and rs3093059 had 0.70- and 0.78-fold lower IMT than men carrying minor-major/major-major genotype. We also observed that the interaction of CRP SNP rs1130864 and rs3093059 with obesity on IMT, hs-CRP and fibrinogen levels. These results support the hypothesis that inflammatory genes are involved in atherosclerosis, most likely via complex gene-gender and gene-obesity interactions.

Association of genetic variants of hemostatic genes with myocardial infarction in Egyptian patients

Hemostatic genes polymorphisms are well known to be associated with venous thrombosis, but their association with arterial thrombosis especially myocardial infarction (MI) remains to be clarified. We investigated the role of three hemostatic gene polymorphisms, prothrombin G20210A, factor XIII (FXIII) Val34Leu (G/T), and fibrinogen-β-455G/A and their coexistence in Egyptian patients with MI. The possible correlation of these polymorphisms with plasma fibrinogen level was also evaluated. The study included 120 patients with MI and 60 healthy volunteers. Gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. Plasma fibrinogen level was determined by ELISA. Our study showed an increased risk of MI with fibrinogen β-455G/A heterozygosity as well as FXIII Val34Leu homo and heterozygosity. In addition, the FXIII T allele (Leu34) and fibrinogen β-455A allele were significantly associated with MI. Conversely, the prevalence of prothrombin mutation did not differ between patients with MI and controls. Combined carriers of FXIII Leu34 and fibrinogen-β455A alleles were at higher risk of MI, whereas combined FXIII Val34Leu and prothrombin 20210A polymorphisms did not show increased risk for MI compared with controls. Plasma fibrinogen levels were significantly higher in patients with MI than controls. In MI patients, plasma fibrinogen levels were significantly higher in those with FXIII GT/TT or fibrinogen β-455 GA, while were significantly lower in those with prothrombin 20210 GA compared with patients with wild type genotypes. In conclusion, our results suggest a possible thrombotic predisposition of FXIII Val34Leu, fibrinogen β-455G/A polymorphisms and their coexistence for MI. These polymorphisms may add complexity to disease pathology by increasing plasma fibrinogen level. Extended studies are needed to confirm our results; nevertheless, these data may be implicated in genetic counseling and screening of high-risk individuals.

Atherosclerotic and thrombotic genetic and environmental determinants in Egyptian coronary artery disease patients: a pilot study

BACKGROUND

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Multiple genetic variants in combination with various environmental risk factors have been implicated. This study aimed to investigate the association of twelve thrombotic and atherosclerotic gene variants in combination with other environmental risk factors with CAD risk in a preliminary sample of Egyptian CAD patients.

METHODS

Twenty three consecutive CAD patients undergoing diagnostic coronary angiography and 34 unrelated controls, have been enrolled in the study. Genotyping was based on polymerase chain reaction and reverse multiplex hybridization. Five genetic association models were tested. Data distribution and variance homogeneity have been checked by Shapiro-Wilk test and Levene test, respectively; then the appropriate comparison test was applied. Spearman's rank correlation coefficient was used for correlation analysis and logistic regression has been performed to adjust for significant risk factors. Clustering the study participants according to gene-gene and gene-environment interaction has been done by Detrended Correspondence Analysis (DCA).

RESULTS

The univariate analysis indicated that the five variants; rs1800595 (FVR2; factor 5), rs1801133 (MTHFR; 5,10-methylenetetrahydrofolate reductase), rs5918 (HPA-1; human platelet antigen 1), rs1799752 (ACE; angiotensin-converting enzyme), and rs7412 and rs429358 (ApoE; apolipoprotein E) were significantly associated with CAD susceptibility under different genetic models. Multivariate analysis revealed clustering of the study population into three patient groups (P) and one control group. FVR2 was the most variant associated with CAD patients, combined with the factor V Leiden (FVL) variant in P1 cluster and with both ACE and MTHFR 667C > T in P2. Whereas, P3 was mostly affected by both MTHFR 667C > T and FXIII (factor 13) V89L mutations. When combined with traditional risk factors, P1 was mostly affected by dyslipidemia, smoking and hypertension, while P2 was mostly affected by their fasting blood sugar levels and ApoE variant.

CONCLUSIONS

Taken together, these preliminary results could have predictive value to be applied in refining a risk profile for our CAD patients, in order to implement early preventive interventions including specific antithrombotic therapy. Further large scale and follow-up studies are highly recommended to confirm the study findings.

Association of Hemostatic Gene Polymorphisms With Early-Onset Ischemic Heart Disease in Egyptian Patients

The association between hereditary thrombophilia and venous thrombosis is well established but controversial data exist with respect to arterial thrombosis. We performed a pilot study on 31 patients with acute myocardial infarction (AMI), 21 patients with unstable angina (UA), and 20 healthy volunteers to investigate the role of various hemostatic gene polymorphisms in young Egyptian patients, who survived their first ischemic heart disease (IHD). Thrombophilic gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. We showed an increased risk of AMI with factor V (FV) Leiden and prothrombin G20210A heterozygosity. The increased risks of UA was associated with GA and A allele of fibrinogen β-455G→A polymorphism. Conversely, factor XIII (FXIII) Val34Leu GT and T allele were protective in the UA group. Nevertheless, the prevalence of FV H1299R, plasminogen activator inhibitor 1 4G/5G, glycoprotein IIIa C1565T, 5,10-methylenetetrahydrofolate reductase C677T, and A1298C mutations did not differ between patients with IHD and controls. The data have clinical implications regarding screening and thromboprophylaxis in high-risk individuals younger than 40 years.

Association analysis of genetic polymorphisms of factor V, factor VII and fibrinogen β chain genes with human abdominal aortic aneurysm

Increased activity of the coagulation system is associated with the increased risk of many arterial thrombotic diseases and atherosclerosis. The purpose of this study was to evaluate the influence of selected polymorphisms in genes coding for coagulation factor V (1691 G/A, the so-called Leiden mutation), factor VII (−323 0/10 bp insertion/deletion) and fibrinogen β chain (−455 G/A) on the risk of abdominal aortic aneurysm, a particular form of atherothrombosis. We conducted a case-control study of 153 Polish patients hospitalized due to abdominal aortic aneurysm (AAA) and compared the results to those obtained from matched healthy control subjects. The polymorphisms were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments. The study revealed that individuals carrying heterozygous genotype GA for the fibrinogen β chain −455 G/A mutation had at least a 2-fold greater likelihood of AAA development compared to control subjects (OR=3.01; 95% CI 1.83–4.96). The cases possessing homozygous mutant genotype (AA) had no significant risk of developing AAA compared to the control subjects (OR=1.12; 95% CI 0.33–2.44; p=0.83). Concerning factor V 1691 G/A and factor VII −323 0/10 bp mutations, we did not find any statistically significant correlation between them and AAA occurrence. In conclusion, we suggest that the −455G/A polymorphism of the fibrinogen β chain gene is a potential genetic marker to identify the risk of AAA.

Association of platelet collagen receptor polymorphisms with premature acute myocardial infarction

The impact of platelet collagen receptor polymorphisms in the pathogenesis of myocardial infarction at young age remains unknown. To determine whether either of the two platelet collagen receptor polymorphisms (GP VI T13254C and GP Ia C807T) was associated with premature acute myocardial infarction. One hundred patients with premature acute myocardial infarction and 100 age-matched controls with normal coronary angiograms were studied. Genotyping was done using PCR followed by restriction fragment length polymorphism (RFLP). GP Ia C807T polymorphism was more frequent in the patient group (65%) than in the control group (53%). However, there was no association between this polymorphism and premature acute myocardial infarction (P = 0.08). The prevalence of T13254C polymorphism did not differ between patients (38%) and controls (33%), and this polymorphism was not associated with premature acute myocardial infarction (P = 0.46). Logistic regression analysis also indicated no association between these polymorphisms and premature acute myocardial infarction (C807T with P = 0.51 and T13254C with P = 0.20). There is no association between GP VI T13254C or GP Ia C807T polymorphisms and premature acute myocardial infarction.

Fibrinogen beta variants confer protection against coronary artery disease in a Greek case-control study

Background

Although plasma fibrinogen levels are related to cardiovascular risk, data regarding the role of fibrinogen genetic variation in myocardial infarction (MI) or coronary artery disease (CAD) etiology remain inconsistent. The purpose of the present study was to investigate the effect of fibrinogen A (FGA), fibrinogen B (FGB) and fibrinogen G (FGG) gene SNPs and haplotypes on susceptibility to CAD in a homogeneous Greek population.

Methods

We genotyped for rs2070022, rs2070016, rs2070006 in FGA gene, the rs7673587, rs1800789, rs1800790, rs1800788, rs1800787, rs4681 and rs4220 in FGB gene and for the rs1118823, rs1800792 and rs2066865 SNPs in FGG gene applying an arrayed primer extension-based genotyping method (APEX-2) in a sample of CAD patients (n = 305) and controls (n = 305). Logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), before and after adjustment for potential confounders.

Results

None of the FGA and FGG SNPs and FGA, FGB, FGG and FGA-FGG haplotypes was associated with disease occurrence after adjustment. Nevertheless, rs1800787 and rs1800789 SNPs in FGB gene seem to decrease the risk of CAD, even after adjustment for potential confounders (OR = 0.42, 95%CI: 0.19-0.90, p = 0.026 and OR = 0.44, 95%CI:0.21-0.94, p = 0.039, respectively).

Conclusions

FGA and FGG SNPs as well as FGA, FGB, FGG and FGA-FGG haplotypes do not seem to be important contributors to CAD occurrence in our sample. On the contrary, FGB rs1800787 and rs1800789 SNPs seem to confer protection to disease onset lowering the risk by about 50% in homozygotes for the minor alleles.