Apolipoprotein E genotypes and risk of diabetic nephropathy.

Genetic susceptibility contributes to the development of diabetic nephropathy. In considering potentially important genetic factors, this study examined the association between genetic polymorphisms in apolipoprotein (apo) E and diabetic nephropathy in 146 patients with insulin-dependent diabetes mellitus (IDDM) of 15 to 21 years' duration. Using a case-control study design, patients with proteinuria (N = 41) (albumin excretion rate (AER) > or = 250 micrograms/min) and patients with microalbuminuria (N = 31) (AER 20 to 250 micrograms/min) were compared with patients who had normoalbuminuria (N = 74) (AER < 20 micrograms/min). Genetic polymorphisms at the apo E locus were identified by the method of denaturing gradient-gel electrophoresis. There was no significant difference in allele frequencies in the proteinuric, microalbuminuric, or normoalbuminuric groups (e2 7.3%, 9.7%, 9.5%; e3 78.1%, 72.6%, 68.2%; e4 14.6%, 17.7%, 22.3%; respectively). The distribution of the apo E genotypes among the three groups of patients was also similar. These results suggest that apo E genotypes are not associated with the development of early or advanced diabetic nephropathy in patients with IDDM.