Association of angiotensin-converting enzyme gene insertion/deletion polymorphism with metabolic syndrome in Iranians with type 2 diabetes mellitus.

BACKGROUND Angiotensin-converting enzyme insertion/deletion polymorphism has been shown to be associated with diabetes, hypertension, coronary artery diseases, and diabetic nephropathy. The objective of this study was to investigate whether angiotensin-converting enzyme gene insertion/deletion polymorphism is associated with metabolic syndrome in Iranians with type 2 diabetes mellitus. METHODS A total of 170 patients with type 2 diabetes mellitus and 91 control subjects were studied. The angiotensin-converting enzyme insertion/deletion polymorphism was determined by polymerase chain reaction (PCR) utilizing specific primers. The definition and criteria of metabolic syndrome used in this study matched that proposed in 1998 World Health Organization classification. RESULTS Of 170 patients studied, 119 (70%) fulfilled the criteria for metabolic syndrome. The prevalence of angiotensin-converting enzyme genotype in the control subjects with DD, ID, and II genotype was 13.2%, 47.3%, and 39.5%, respectively. In patients with metabolic syndrome, the prevalence was 26.9%, 56.3%, and 16.8%, respectively; in patients without metabolic syndrome, it was 21.6%, 62.7%, and 15.7%, respectively. The angiotensin-converting enzyme insertion/deletion polymorphism was not significantly associated with presence of metabolic syndrome in patients with type 2 diabetes (P=0.711). The frequency of DD genotype in the metabolic syndrome group (26.9%) was higher than that (21.6%) in those without metabolic syndrome (P=0.447) and the control group (13.2%, P=0.02). The frequency of D allele in metabolic syndrome patients was 55.1% as compared to those patients without metabolic syndrome (52.9%, P=0.72) and the control subjects (36.8%, P<0.001). CONCLUSION It seems that the DD genotype and/or D allele of angiotensin-converting enzyme gene may increase the risk for developing type 2 diabetes mellitus, but not metabolic syndrome.