Interestingly, secretion and mature ameloblast-specific genes (Satb2, Sox21, Mafb, Foxq1, Foxo1, Cdkn2b, Runx2, Klf5, Prdm1, Gm17660) and stem cell genes (Six1, Lrig1) were significantly downregulated in incisors of T2DM mice, whereas the major ameloblast specific genes such as Enam, Klk4, Amelx, Ambn, Mmp20 were not changed (Figure 4A, Table 5 left). The gene discussed is KLK4; the disease is type 2 diabetes mellitus.