Grant et al.[10] reported on the association of a common microsatellite (DG10S478) within intron 3 of the transcription factor 7–like 2 gene (TCF7L2) with type 2 diabetes in an Icelandic case–control sample and replicated this result in two additional case–control cohorts of white patients. Here, TCF7L2 is linked to type 2 diabetes mellitus.