Objective: To investigate the association between angiotensin converting enzyme (ACE) gene locus rs1799752 insertion/deletion (I/D) polymorphism and diabetic retinopathy (DR) in type 2 diabetes mellitus.
Methods: Case-control study. Type 2 diabetes patients were recruited and assigned into DR group, which included proliferative diabetic retinopathy (PDR) group or diabetes without retinopathy (DWR) group. Volunteers without diabetes from the same community were recruited as the control group. PCR and agarose gel electrophoresis methods were adopted to determine the rs1799752 I/D polymorphism genotypes of the ACE gene. The frequency of genotypes and alleles was compared among the various groups.
Results: Four hundred and twelve diabetes patients: (207 subjects of DR, including 53 subjects of PDR and 205 subjects of DWR) and 97 non-diabetic control subjects were included in the study. The frequencies of the I and D alleles of ACE rs1799752 polymorphism were 54.1% and 45.9%, respectively, in the DR group, 52.8% and 47.2% in the PDR group, and 48.0% and 52.0% in the DWR group. There were no statistical differences between DR and DWR groups (χ(2) = 3.02, P > 0.05) or between PDR and DWR groups (χ(2) = 0.77, P > 0.05). Moreover, there were no statistical differences in the distribution of the ACE genotypes between DR group (II 25.1%, ID 58.0%, DD 16.9%) and DWR group (II 22.0%, ID 52.2%, DD 25.9%) (χ(2) = 4.92, P > 0.05) or between PDR group (II 20.7%, ID 64.2%, DD 15.1%) and DWR group (χ(2) = 3.19, P > 0.05). No statistical differences were found in the frequencies of the I and D alleles, and the distributions of I/D genotypes between diabetic group and the control group (χ(2) = 0.25, 4.98; P > 0.05). In the multiple regressions model including clinical factors such as the age of onset of diabetes, urinary albumin, insulin usage, creatinine, glycated hemoglobin, fast glucose, and the use of ACE inhibitor, no association was found between ACE gene polymorphism and DR (OR = 0.80, 95%CI: 0.59 - 1.09) or PDR (OR = 1.23, 95%CI: 0.78 - 1.93).
Conclusion: There is no association between ACE rs1799752 gene insertion/deletion (I/D) polymorphism and DR in patients with type 2 diabetes mellitus.