Polymorphism of the angiotensin I-converting enzyme gene in diabetic nephropathy in type II diabetic patients with proliferative retinopathy

Abstract

Recently, deletion (D)/insertion (I) polymorphism in the Angiotensin I- converting enzyme (ACE) gene has been suggested to be related to the development of diabetic nephropathy in type I diabetes mellitus. This hypothesis, however, remains controversial. Differences in clinical states between patients, especially in glycemic control or duration of diabetes, could be responsible for these contradictory results. In this study we examined the relationship between D/I polymorphism of the ACE gene and diabetic nephropathy in type II diabetic patients who had already developed proliferative retinopathy (n = 45), and were thought to have been in a hyperglycemic state for long enough to develop microangiopathy. The patients were divided into two subgroups: 24 with nephropathy (albumin excretion rate:AER ≤ 20 μg/min) and 21 without (AER < 20 μg/min). There was no difference in the duration of diabetes, HbAlc levels or average blood pressure over the previous year between these subgroups and other clinical characteristics were comparable. Patients without nephropathy exhibited allele I more often than those with nephropathy (p = .025). AER was lowest in genotype II and highest in genotype DD patients but the difference was not statistically significant (p = .07). From these findings, it was concluded that genotype II for the ACE gene could be a marker for reduced risk of diabetic nephropathy.