Our results may have shown the clinical differences between WS II patients with SOX10 and MITF mutations, and between WS II and WS I. However, gene test is as necessary as clinical investigation for the accurate diagnosis and subtype confirmation (Hageman and Delleman, 1977; Read and Newton, 1997; Pingault et al., 2010; Song et al., 2016; Li et al., 2019). This evidence concerns the gene MITF and Werner syndrome.