Prediabetes genes in Pima and Amish

Abstract

Type 2 diabetes mellitus has a global distribution, yet its prevalence varies from country to country with the highest rates being reported in developed and developing countries [ 1– 3 ]. Studies comparing rural vs. Urban dwelling, as well as migration studies, indicate that change towards a Westernized lifestyle is associated with a dramatic increase in the prevalence rates for this disease [ 4 ]. This environmental impact has been documented in urbanized Paci fi c Island populations and migrant Asian Indians [ 5– 9 ]. However, among individuals living in a similar environment, genetics has a clear in fl uence on prevalence rates of type 2 diabetes. Different ethnic groups living within the same geographic region often have different prevalence rates of this disease [ 10 ]. For example, Latinos are the largest minority population in the United States and have a two to fourfold higher prevalence of diagnosed diabetes as compared to Caucasians [ 11, 12 ]. Rates of diabetes also differ between families, where siblings of affected individuals have an increased risk, which again suggests a familial component. Some of the strongest evidence for a genetic basis for type 2 diabetes comes from studies in twin pairs. Both monozygotic and dizygotic twin pairs share equally in a family environment, yet there is a higher concordance rate for type 2 diabetes among monozygotic twins who share 100% of their DNA as compared to dizygotic twins who share on average 50% of their DNA [ 13, 14 ].