A 63bp deletion in the promoter of RAGE correlates with a decreased risk for nephropathy in patients with type 2 diabetes

Several polymorphisms have been identified in the RAGE-promoter region that might modulate the outcome of disease. Here we analyse the association of a 63bp deletion (delta63) spanning from bp-407 to bp-345 with diabetic nephropathy. The deletion was determined using the polymerase chain reaction (PCR) in a cross-sectional study with 1087 patients with type 1 diabetes (n = 559) and type 2 diabetes (n = 528). 475 patients with osteoporosis served as disease independent control. The prevalence of the heterozygous genotype did not significantly differ between the three groups (type 1: 2.15%, type 2: 2.27%, controls: 1.47%), indicating that heterozygous delta63 is not related to the manifestation of diabetes. Homozygous carriers were not identified in this study. The heterozygous delta63 genotype, was associated with a reduced prevalence of diabetic nephropathy in patients with type 2 diabetes (OR = 0.06; 95% CI: [0.05, 0.07]), but not in patients with type 1 (OR = 1.49; 95% CI: [1.14, 1.94]). We conclude, that patients with type 2 diabetes and the 63bp deletion in the promoter of RAGE seem to be protected from diabetic nephropathy. The observed difference between type 1 and type 2 diabetes might point to diverse pathomechanisms of nephropathy in both types of diabetes.