Association between apolipoprotein E polymorphism and nephropathy in Iranian diabetic patients.

Approximately one-third of diabetic patients develop evidence of nephropathy. Pathogenesis of diabetic nephropathy (DN) remains unclear; however, some genetic and metabolic risk factors have been determined for the development and progression of DN. In the recent genetic studies, polymorphism of apolipoprotein E (ApoE) gene has been reported as a risk factor for the development of DN; however, the results are inconsistent. The aim of the present study was to evaluate the association between ApoE polymorphism and nephropathy in Iranian patient with type 2 diabetes. A total of 197 patients with type 2 diabetes in two groups with and without nephropathy (n = 99 and n = 98, respectively) participated in this case-control study. ApoE genotype was determined by restriction fragment length polymorphism analysis. Biochemical factors of all patients were measured. The frequency of Apo ε4 allele was significantly (P <0.05) lower in DN patients (10.6%) than in diabetic patients without nephropathy (20.4%). No significant difference was observed between the groups regarding Apo ε2 and Apo ε3 allele frequencies. Serum level of total and low-density lipoprotein cholesterol in Apo ε2 carriers was lower than Apo ε3 and Apo ε4 carriers, but this difference was not statistically significant. Frequency of Apo ε4 allele is higher in diabetic patients without nephropathy than DN participants. Given to the result, it seems that Apo ε4 has a protective effect in diabetic patients against nephropathy.