Association of polymorphisms in the insulin-degrading enzyme gene with type 2 diabetes in the Korean population

Insulin-degrading enzyme (IDE) is a metalloproteinase which degrades insulin and terminates its action. Homologous deletion of IDE gene resulted in hyperinsulinemia and glucose intolerance in a rat model of type 2 diabetes mellitus. Several genetic association studies examined IDE as a susceptibility gene for type 2 diabetes in European descents. Here we investigated the genetic association of IDE polymorphisms with the risk of type 2 diabetes and its related phenotypes in the Korean population. Among six single nucleotide polymorphisms analyzed, g.−179T > C (OR = 1.73, P = 0.04), and g.IVS18+99G > A (OR = 1.23, P = 0.02) revealed borderline association with increased risk of type 2 diabetes. Combining our results with previous data obtained from the European population, g.−179T > C (OR = 1.11, P = 0.03), and g.IVS24−64A > T (OR = 1.18, P = 0.005) showed significant association with type 2 diabetes. Haplotype consisting of common alleles of the six polymorphisms was associated with decreased risk of type 2 diabetes (OR = 0.82, P = 0.02). However, none of the polymorphisms was significantly associated with metabolic phenotypes. We can conclude that variations in IDE might contribute to diabetes susceptibility in the Korean population.