Objectives To investigate the relationship between plasminogen activator inhibitor-1(PAI-1) promotor region gene 4G/5G polymorphism and pulmonary thromboembolism (PTE) and detect whether it plays an important role in the pathogenesis of pulmonary thromboembolism.

Methods Fifty-eight patients with PTE and 57 sex and age matched healthy controls were recruited in this study. Genome DNA was extracted from whole blood using phenol-chloroform. Subjects were genotyped for the 4G/5G polymorphism of PAI-1 gene using polymerase chain reaction based restriction fragment length polymorphism analysis.

Results Significant differences were found in the frequencies of genotype 4G/4G, 4G/5G and 5G/5G. The recessive allele model was informative and the odd ratio of 4G/4G genotype was much higher compared with that of other two genotypes. After further stratification,we found that 4G/4G genotype was bound to be associated with high risk of PTE for those individuals without existing traditional environment risk factors.

Conclusions This study shows that 4G/5G polymorphism of PAI-1 gene is associated with PTE and 4G allele is recessive. Our results indicates that 4G/4G genotype increases the risk of PTE for individuals who have no traditional risk factors of PTE.