"Consistent with the previous findings showing that such set of SNPs may explain only a small fraction (2–3%) ofthe trait variation (Saxena et al. 2007), we have also found that the predictive value of these findings is relatively limited.Type 2 diabetes susceptibility loci in the Ashkenazi Jewish population.
For most individuals, the genotypic information will only modestly alter their baseline risk to develop T2D. Only for a small fraction of the population (about 3%), the genetic information may indicate a decrease or increase of the baseline risk by twofold (upwards or downwards). Consequently, at present, the use of genetic information by clinicians for the identification of patients at risk to develop T2D does not seem too relevant. Nevertheless, it is important to emphasize that the value of gene discovery lies primarily in the understanding of the disease as a means to develop efficient therapies."
Bronstein M, Pisanté A, Yakir B, Darvasi A.
Human Genetics 2008 Aug;124(1):101-4.
Abstract: Until last year, type 2 diabetes (T2D) susceptibility loci have hardly been identified, despite great effort. Recently, however, several whole-genome association (WGA) studies jointly uncovered 10 robustly replicated loci. Here, we examine these loci in the Ashkenazi Jewish (AJ) population in a sample of 1,131 cases versus 1,147 controls. Genetic predisposition to T2D in the AJ population was found similar to that established in the previous studies. One SNP, rs7754840 in the CDKAL1 gene, presented a significantly stronger effect in the AJ population as compared to the general Caucasian population. This may possibly be due to the increased homogeneity of the AJ population. The use of the SNPs considered in this study, to identify individuals at high (or low) risk to develop T2D, was found of limited value. Our study, however, strongly supports the robustness of WGA studies for the identification of genes affecting complex traits in general and T2D in particular.