Background: There is agreement that a family history of hypertension (HT), is a predictor for the risk of diabetic nephropathy (DN) in patients with type 2 diabetes, and possibly also type 1 diabetes. It follows that genes related to the risk of hypertension must also be considered candidate genes for DN. The 235T allele of the angiotensinogen gene was found to be related to primary HT.
Methods: To examine whether it is predictive for DN as well, we examined the angiotensinogen gene polymorphism in 230 healthy local controls, 423 patients with type 1 diabetes (n = 180 with DN; n = 243 without DN) and 663 patients with type 2 diabetes (n = 310 with DN; n = 353 without DN). The angiotensinogen gene M235T polymorphism was determined using PCR amplification.
Results: The following results were obtained (i) no significant difference of genotype distribution (type 1: MM/MT/TT (%) 27.6/57.2/15.2 vs 27.2/56.1/16.7 (P = 0.92); type 2; MM/MT/TT (%) 31.7/48.2/2/20.1 vs. 32.9/46.8/20.3 (P = 0.93) or allele frequencies (type 1: M 0.56 vs. 0.55 (P = 0.795); type 2; M 0.56 vs. 0.56 (P = 0.86)) was found, between diabetic patients with or without DN, (ii) no difference was found between normotensive and hypertensive diabetic patients.
Conclusion: The data argue against a role of the angiotensinogen gene M235T polymorphism in the manifestation of diabetic nephropathy or hypertension in diabetic patients.