D'Annunzio et al. (2008) evaluated six WS1 patients in five Italian families and noted that the same mutation could lead to different phenotypes, also consistent with our study. This finding suggested that the pathogenesis of WS1 was not only dependent on the mutation of WFS1, but also may be related to other genetic or environmental factors, such as modifier genes. The gene discussed is WFS1; the disease is Waardenburg syndrome type 1.