Objectives: To investigate the relationship between the beta-fibrinogen gene -455A/G polymorphism and plasma fibrinogen level and to determine the influence of the mutation on ischemic stroke.
Methods: Ninety-one patients (63.5 +/- 10.1 years) with ischemic stroke and 74 elderly control subjects (60.6 +/- 10.8 years) without any thromboembolic events and 98 healthy blood donators as young control (37.5 +/- 13.3 years) were enrolled in this trial. The beta-fibrinogen gene -455A/G polymorphism was analyzed for all subjects by PCR-RFLP with the restrictive enzyme Hae III, while plasma fibrinogen levels were obtained from the prothrombin time (PT) assay. For statistical analysis, the parameters were compared between any two different groups by the unpaired Student's t test and the Chi-square test. Before analysis, log transformations for concentrations of fibrinogen were carried out.
Results: H2 allele frequency was higher in male ischemic stroke patients than in the elderly control (22.7% vs 7.1%, chi(2) = 5.56, P < 0.02). There was no significant difference between the female groups. In those patients without any thromboembolic events (both elderly and young control groups), the frequency of H2 decreased with age (< or = 40, 21.3%; 41 - 59, 15.4%; and > or = 60, 10.2%). In the male elderly and young control groups, the level of plasma fibrinogen was lower in the H1H1 genotype (287 +/- 96 mg/dl and 234 +/- 58 mg/dl) than in H1H2 and H2H2 (331 +/- 44 mg/dl and 307 +/- 55 mg/dl; t = 2.53 and 9.67, P < 0.05). In the female elderly groups, this tendency was not found.
Conclusion: Plasma fibrinogen expression is affected by the beta-fibrinogen gene -455A/G polymorphism, and the H2 allele may be a risk factor for ischemic stroke in Chinese males.