Gene polymorphism but not catalytic activity of angiotensin I-converting enzyme is associated with coronary artery disease and myocardial infarction in low-risk patients.

BACKGROUND

An insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene has been postulated to be associated with an increased risk of coronary artery disease (CAD) and myocardial infarction (MI).

METHODS AND RESULTS

In the present study, the effects of I/D gene polymorphism and of ACE activity on CAD and MI were investigated in 920 individuals who underwent coronary angiography for diagnostic purposes. In the total population and in all CAD and MI groups, a strong association was observed between the gene polymorphism and ACE activities; DD genotypes had approximately twofold higher ACE activities than II genotypes. Although classic risk and protective factors of CAD and MI were identified, associations of ACE genotype and of ACE activity to CAD and MI were not detected in the total population. Among subjects defined to be at lower risk of MI by low body mass index and low cigarette consumption, however, an association of the DD genotype with MI was found. Exclusion of individuals with triglyceride levels > 140 mg/dL and cholesterol levels > 180 mg/dL revealed an association of the DD genotype with CAD. An association of the ACE activity with CAD or MI could not be demonstrated in any of the low-risk populations.

CONCLUSIONS

Increased ACE activity obviously is not a risk factor of CAD or MI. The importance of the deletion polymorphism for the development of CAD and MI may be restricted to individuals without classic risk factors.