Increased frequency of angiotensin-converting enzyme DD genotype in patients with type 2 diabetes in Taiwan.

BACKGROUND: Diabetes is one of the major causes of end-stage renal failure in the Taiwanese population. Previous studies have shown that angiotensin-converting enzyme (ACE) inhibitor can improve glucose utilization and suppress hepatic glucose production and the renin-angiotensin system may play an important role in the initiation and progression of diabetic nephropathy. Thus, ACE gene polymorphism may be associated with type 2 diabetes and diabetic nephropathy. METHODS: To investigate the distribution of ACE-I/D genotype in type 2 diabetes and diabetic nephropathy, we examined 336 patients with type 2 diabetes (157 without nephropathy and 179 with nephropathy) and 263 age-matched normal controls. The diagnosis of nephropathy was made when daily protein loss exceeded 500 mg. ACE gene polymorphism was analysed by use of polymerase chain reaction. RESULTS: Our study revealed that the frequency of the D allele of the ACE gene was 29.3% in normal controls. The frequency of ACE DD genotype was significantly higher in type 2 diabetics compared with normal controls (18.2 vs 9.1%, P<0.01). The frequency of ACE DD genotype in patients with diabetic nephropathy was significantly higher than in patients without nephropathy (22.3 vs 13.4%, P<0.05). To determine whether ACE gene polymorphism was associated with the severity of diabetic nephropathy, we divided patients with diabetic nephropathy into dialysis and non-dialysis groups. The frequency of ACE DD genotype in the dialysis group was significantly higher than in non-dialysis group (28.7 vs 15.3%, P<0.05). CONCLUSION: Our results indicate that the frequency of ACE DD genotype is markedly higher in patients with type 2 diabetes, and the ACE DD genotype is significantly associated with diabetic nephropathy.