PAX3 and Waardenburg syndrome: Mutations in PAX3 cause Waardenburg syndrome type 1 and Waardenburg syndrome type 3 (Cao and Wang, 2000; Pingault et al., 2002; Mollaaghababa and Pavan, 2003; Baxter et al., 2004), At the same time, PAX3 plays an important role in the regulation of normal cell apoptosis, proliferation and differentiation.