The identified single-nucleotide polymorphism (SNP) rs7903146 is located in the third intron of TCF7L2 and has been estimated to contribute to 10–25% of all cases of diabetes lean patients (6) TCF7L2 lies at the foot of the wingless (Wnt) signaling pathway activated both by Wnt ligands and by certain growth factors (e.g. insulin and IGF-1), which act through receptor tyrosine kinases (7). This evidence concerns the gene TCF7L2 and diabetes mellitus.