We had also identified novel genes from tooth germ complementary DNA library, namely Ameloblastin (Ambn), Epiprofin (Epfn), and AmeloD (Dhamija et al., 1999; Nakamura et al., 2004; He et al., 2019), and each of these knockout mice models showed severe enamel hypoplasia (Fukumoto et al., 2004; Nakamura et al., 2008, 2017; Aurrekoetxea et al., 2016; Chiba et al., 2019). This evidence concerns the gene SP6 and dental enamel hypoplasia.