In this study, 50 Chinese Han deaf patients with WS type I and II were clinically characterized and genetically screened for mutations in PAX3, MITF, SOX10, SNAI, EDN3 and EDNRB. Our results showed that heterozygous mutations in MITF and SOX10, two major causes of WS2, have distinguishable de novo rates and clinical features. This evidence concerns the gene SOX10 and Waardenburg syndrome type 2.