Objective: To explore the relationship between beta-fibrinogen gene -455A/G polymorphism and plasma fibrinogen level and to determine the influence of the mutation on ischaemic stroke.
Methods: Ninety-one patients (63.5 +/- 10.1 years) with ischaemic stroke, 74 control patients (60.6 +/- 10.8 years) without any thromboembolic events and 98 healthy blood donors (37.5 +/- 13.3 years) were enrolled in this trial. beta-fibrinogen gene -455A/G polymorphism was analyzed from all subjects by polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) with restrictive enzyme Hae III. Plasma fibrinogen levels were obtained from prothrombin time (PT) assay. The parameters were compared between any two different groups by unpaired t-test and Chi-square test. Before the analysis, log transformation was carried out for concentrations of fibrinogen.
Results: Frequency of H2 allele was higher in male patients with ischaemic stroke than in control patients (22.7% vs 7.1%, chi(2) = 5.56, P < 0.02). There was no significant difference in female patients. In the subjects without any thromboembolic events (including control patients and healthy blood donors), frequency of H2 decreased with age (>/= 40, 21.3%; 41 approximately 59, 15.4%; >/= 60, 10.0%). Among male control patients and healthy blood donors, the level of plasma fibrinogen was lower in the H1H1 genotype (287 g/L +/- 96 g/L and 234 g/L +/- 58 g/L) than in H1H2 and H2H2 genotypes (331 g/L +/- 44 g/L and 307 g/L +/- 55 g/L; t = 2.53 and 9.67, P < 0.05); among females, this tendency was not found.
Conclusion: Plasma fibrinogen expression is affected by the beta-fibrinogen gene - 455A/G polymorphism. H2 allele is a risk factor for ischaemic stroke in Chinese men.