Objective: The IGF-II receptor gene (IGFIIR) is located at chromosome 6q26, a region that harbors a genetic marker linked to insulin-resistant traits in Mexican–Americans. In the present study conducted in Spaniards, we tested a common polymorphism in IGFIIR for association with type 2 diabetes and insulin-resistant traits.
Design: Case–control association study.
Methods: One hundred and forty-five type 2 diabetic patients and 217 non-diabetic controls were genotyped for the ACAA-insertion/deletion polymorphism at the 3′ UTR of IGFIIR. Phenotyping included anthropometrics and a metabolic profile, including serum lipid levels and surrogate indexes of insulin resistance whenever possible.
Results: Diabetic patients were more frequently homozygous for the wild type 144 bp allele of IGFIIR compared with controls (diabetic patients 77.2%, controls 51.6%, P<0.001) suggesting a potential protective role against type 2 diabetes for the IGFIIR 140 bp variant. Carrying 140 bp alleles was associated with an odds ratio of having diabetes of 0.290 (95% confidence interval 0.109–0.770), and controls homozygous for the wild type 144 bp allele presented with lower insulin and triglyceride levels, which are proxies for insulin resistance.
Conclusions: The ACAA-insertion/deletion polymorphism at the 3′ UTR of IGFIIR is associated with type 2 diabetes and influences surrogate markers of insulin resistance in non-diabetic subjects.