Objective: To investigate whether there is an association between the insertion deletion polymorphsim of human angiotensin I converting enzyme gene (ACE) and pulmonary thromboembolism and whether D allele increases the risk of pulmonary thromboembolism in Chinese population.
Methods: Seventy-two patients with pulmonary thromboembolism and 72 sex and age matched healthy controls were recruited in this study, all patients were diagnosed by lung ventilation/perfusion scan and/or ultrafast CT as well as medical history. Risk factors of venous thrombosis and pulmonary thromboembolism were inquired. Genome DNA was extracted from whole blood using phenol-chloroform. Subjects were genotyped for the I/D polymorphism of ACE gene using polymerase chain reaction based restriction fragment length polymorphism analysis.
Results: (1) The incidences of trauma, operation, phlebitis and venous varicose were significant higher in the patient than in controls. No significant difference were found in the family history of pulmonary thromboembolism and cardiovascular diseases, personal history of oral contraceptive, cigarette smoking and alcohol drinking between the patient and controls. (2) Frequencies of allele I and D in the controls were 0.66 and 0.34 respectively, the distribution of genotypes met the in Hardy-Weinberg equilibrium. No significant differences were found in the frequencies of genotype II, ID and DD between patients and controls. (3) The recessive allele model was informative and the odds ratio of DD genotype was 2.51 (P < 0.05) compared with the other two genotypes. (4) After further stratification, we found DD genotype was bound to be associated with an 2.64-fold risk of pulmonary thromboembolism for those individuals without existing traditional environmental risk factors and 3.36-fold risk for individuals with medical history of venous thrombosis (P < 0.05).
Conclusion: This study shows that I/D polymorphism of ACE gene is associated with pulmonary thromboembolism in Chinese population and allele D is recessive. Our results indicate that DD genotype increases the risk of pulmonary thromboembolism for individuals who have no traditional risk factors of venous thrombosis or pulmonary thromboembolism and also for those with personal history of venous thrombosis.