Angiotensin Converting Enzyme Insertion/Deletion (ACE I/D) and Methylene Tetrahydrofolate Reductase C677T (MTHFR C677T) genetic polymorphisms in the pathogenesis of abdominal aortic aneurysms (AAA)

Objectives: The aims of the study were to identify associations between ACE I/D and MTHFR C677T and AAA. Methods: A retrospective case-control study in which polymerase chain reaction (PCR) methodology was employed to identify associations between ACE I/D and MTHFR C677T polymorphisms and AAA. DNA was extracted from reasonably matched cases and controls after suitable screening for group assignment. There were a total of 1352 subjects genotyped for the MTHFR C677T polymorphism comprising 674 controls and 678 cases. Comparative figures for ACE I/D polymorphism genotyping were 812 and 1107, respectively. All statistical analyses were conducted using R programming software with user-written codes. Results: The ACE II, ID and DD genotype distributions in controls (177, 410 and 225) and cases (218, 529 and 270) were in Hardy-Weinberg Equilibrium (HWE), P=0.21.There was no difference in allele (“I” and “D”) distributions between cases and controls (odds ratio(OR),1.001; 95% CI, 0.88-1.14; P =0.98). There was no difference between cases and controls in terms of the II, ID and DD distributions irrespective of the genetic model adopted. Similarly, the MTHFR CC, CT and TT genotype distributions for controls (358, 257 and 59) and cases (321, 292, and 65) were in HWE (P = 0.39) but the allele (“C” and “T”) distributions were not significantly different between groups (OR, 1.172; 95%CI, 0.99 -1.38; P=0.057). However, MTHFR C677T polymorphism was significantly associated with AAA under a heterozygote co-dominant (OR, 1.27; 95% CI, 1.01-1.59) and dominant (CT+TT vs. CC) (OR, 1.26; 95% CI, 1.02-1.56; P= 0.034) genetic inheritance models, respectively. However, there was no association under the over-dominant (CT vs. CC +TT) model (OR, 1.23; 95% CI, 0.99-1.53; P=0.06). Similarly, the trend test was not significant (OR, 1.14; P=0.06) and when corrected for confounders. Conclusion: The ACE I/D and MTHFR C677T genetic polymorphisms were not independently associated with AAA in this study.