Summary: | <p>Abstract</p> <p>Background</p> <p>Several polymorphisms within the renin-angiotensin system cluster of genes have been associated with the advent of coronary artery disease (CAD) or related pathologies. We investigated the distribution of 5 of these polymorphisms in order to find any association with CAD development and distinguish if any of the biochemical and behavioural factors interact with genetic polymorphisms in the advent of the disease.</p> <p>Methods</p> <p><it>ACE </it>I/D (rs4340), <it>ACE </it>A11860G (rs4343), <it>AT1R </it>A1166C (rs5186), <it>AGT </it>T174M (rs4762) and <it>AGT </it>M235T (rs699) gene polymorphisms were PCR-RFLP analysed in 298 CAD patients and 510 controls from Portugal. Several biochemical and behavioural markers were obtained.</p> <p>Results</p> <p><it>ACE </it>I/D DD and <it>ACE</it>11860 GG genotypes are risk factors for CAD in this population. The simultaneous presence of <it>ACE </it>I/D I and <it>ACE</it>11860 A alleles corresponds to a significant trend towards a decrease in CAD incidence. We found several synergistic effects between the studied polymorphisms and classical risk factors such as hypertension, obesity, diabetes and dyslipidaemia: the presence of the DD genotype of <it>ACE </it>I/D (and also <it>ACE</it>11860 GG) increases the odds of developing CAD when associated to each one of these classical risk factors, particularly when considering the male and early onset CAD subgroup analysis; <it>AGT</it>235 TT also increases the CAD risk in the presence of hypertension and dyslipidaemia, and <it>AT1R</it>1166 interacts positively with hypertension, smoking and obesity.</p> <p>Conclusion</p> <p><it>ACE </it>polymorphisms were shown to play a major role in individual susceptibility to develop CAD. There is also a clear interaction between RAS predisposing genes and some biochemical/environmental risk factors in CAD onset, demonstrating a significant enhancement of classical markers particularly by <it>ACE </it>I/D and <it>ACE</it>11860.</p>
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