It also promotes the development of the peripheral nervous system and embryonic neural cells.[49] Mutations in SOX10 cause Waardenburg syndrome and account for 15% of type II and 45–55% of type IV cases.[50, 51] WS is both clinically and genetically a heterogeneous condition, which results from melanocyte deficiency of the skin and the absence of stria vascularis in the cochlea.[52] It is characterized by depigmented patches of the hair and skin, heterochromia irides, or vivid blue eyes along with sensorineural hearing loss. The gene discussed is SOX10; the disease is Werner syndrome.