The role of the I/D polymorphism in the angiotensin-converting enzyme gene in selected cardiovascular diseases

Angiotensin converting enzyme (ACE) plays an essential role in the functioning of two important systems in the human body by catalysing the synthesis of angiotensin II in the renin-angiotensin-aldosterone system and by degrading bradykinin in the kinin-kallikrein system. The wide range of functionality of those systems allows us to assume that ACE can be involved in the development of many cardiovascular conditions. It has been shown that ACE activity is largely genetically determined. More than nine hundred various polymorphisms, mostly single nucleotide polymorphisms, have been detected in the ACE gene; however, the most researched one is still the insertion/deletion polymorphism located in intron 16, which determines fifty per cent of variability of ACE activity. It is stated that DD homozygotes have the highest ACE serum activity, which can indicate a higher risk of developing certain cardiovascular diseases in patients with this genotype. Therefore, the I/D polymorphism has been analysed in thousands of studies, mainly in the context of cardiovascular conditions risk. The correlation between ACE I/D polymorphism and the risk of particular diseases, its cooperation with other risk factors or its influence on therapy among patients with conditions such as coronary artery disease, hypertension, atrial fibrillation and heart failure have been searched. Unfortunately, the results of those studies have often turned out ambiguous or even contrary. We herein present a summary of the most essential analyses and current knowledge about the role of the I/D polymorphism in the evaluation of risk and treatment efficacy of most common cardiovascular conditions.