Shu et al reported that the reduced levels of TCF7L2 gene expression in T2DM correlated with the down-regulation of receptors for glucagon-like peptide 1 (GLP-1R) and glucose-dependent insulinotropic polypeptide (GIP-R) expression, and impaired β-cell function (10). The gene discussed is TCF7L2; the disease is type 2 diabetes mellitus.