It remains unclear how UCP2 affects the development of diabetes, yet some research groups have used either UCP2-overexpressing mouse islets or β-cell-specific UCP2-knockout mice (Chan et al., 1999; Produit-Zengaffinen et al., 2007; Robson-Doucette et al., 2011; Zhang et al., 2001). This evidence concerns the gene UCP2 and diabetes mellitus.