The identification of common genetic variants that are reproducibly associated with type 2 diabetes has accelerated considerably with the availability of results from genome wide association studies (GWAS) of prevalent cases and controls [1-6]. However, the discovered associations only account for a relatively small proportion of the heritable component [7]. Interactions between genetic factors and lifestyle exposures, gene-gene interaction, and genetic variation other than common single nucleotide polymorphisms (SNPs) are likely to be important factors that contribute to the remaining variance [8], but have not been systematically explored.
