Genotypic interactions of renin-angiotensin system genes in myocardial infarction.
BACKGROUND
Three-gene interactions among the genetic polymorphisms of the renin-angiotensin system (RAS) associated with acute myocardial infarction (AMI) have not been examined in a single population. We hypothesized that all types of gene-to-gene associations may occur in AMI, but that some will have a higher risk, depending on the gene frequencies.


METHODS
Polymorphisms of the AGT (M235T), ACE (I/D) and AGTR1 (A1166C) genes in AMI patients and controls were analyzed using the polymerase chain reaction. Classic coronary risk factors were analyzed in all individuals.


RESULTS
Logistic regression analysis of these factors and the genetic polymorphisms demonstrated that smoking, family history of CAD, arterial hypertension and total cholesterol were the most significant contributors to AMI. The genotypic frequencies for all three genes alone were similar between the infarction and control groups, with no increased risk of developing AMI. Double homozygous combinations for normal alleles (MM of AGT, II of ACE and AA of AGTR1) had a lower risk of AMI (odds ratio<0.38), indicating a protective effect in these individuals. In genotypic combinations that included at least one unfavorable allele, the risk (odds ratio) of developing AMI was 2.92, 2.63 and 2.68 for AGT vs. ACE, AGT vs. ATR1 and ACE vs. AGTR1, respectively. The positive interaction among the three genes and the risk of AMI had an odds ratio of 3.78 with a 95% CI of 0.88-12.85.


CONCLUSIONS
The risk of developing AMI is higher whenever there are unfavorable alleles in gene-to-gene associations in the RAS.
Araújo
Messias Antônio
MA
Department of Internal Medicine, Medical School, Federal University of Uberlândia, Brazil. messiasaa@bol.com.br
Goulart
Luiz Ricardo
LR
Cordeiro
Elisângela Rosa
ER
Gatti
Renata Ríspoli
RR
Menezes
Bruno Soares
BS
Lourenço
Clauber
C
Silva
Heyder Diniz
HD
D000293:Adolescent; D000483:Alleles; D000808:Angiotensinogen / Q000097:blood / Q000235:genetics*; D015415:Biomarkers / Q000097:blood; D004247:DNA / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D009154:Mutation; D009203:Myocardial Infarction / Q000097:blood / Q000235:genetics*; D016017:Odds Ratio; D007703:Peptidyl-Dipeptidase A / Q000097:blood / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D044140:Receptor, Angiotensin, Type 1 / Q000097:blood / Q000235:genetics*; D012084:Renin-Angiotensin System / Q000235:genetics*; D012307:Risk Factors
D015415:Biomarkers; D044140:Receptor, Angiotensin, Type 1; D000808:Angiotensinogen; D004247:DNA; D007703:Peptidyl-Dipeptidase A