RAGE polymorphisms and the heritability of insulin resistance: the Leeds family study.

UNLABELLED Activation of the receptor for advanced glycation end-products (RAGE) leads to a cascade of pro-inflammatory and pro-coagulant responses which are important in the pathogenesis of the vascular complications of diabetes mellitus. It is known that pro-inflammatory mechanisms underpin the development of type 2 diabetes. Our hypothesis is that RAGE may be involved in the evolution of insulin resistance in addition to mediating glucotoxic complications of diabetes mellitus. METHODS To investigate the relationship between RAGE allelic variation and insulin resistance, the Gly82Ser variant and three promoter variants (-429, -374, 63 bp deletion) were studied in 480 subjects of known relationship from 89 families characterised for insulin resistance (using homeostasis model assessment [HOMA]) and for atherothrombotic risk. Carriage of the -429 C allele was weakly associated with increased insulin resistance (p = 0.02) when pedigree analysis was performed using SOLAR software. RESULTS Insulin resistance was estimated to have a heritability of 25.8% before the addition of covariates. Analysis of the relationship between RAGE and insulin resistance indicated that the -429 polymorphism reduced the unexplained heritability of insulin resistance after adjusting for covariates (age, sex, body mass index) from 17.5% of the total variance to 15.6% of the total variance. CONCLUSIONS These preliminary results indicate that the RAGE gene may affect the development of insulin resistance or be in linkage disequilibrium with a locus involved in this process.