no telecanthus, or apparent wider eye gap), but with the addition of Hirschsprungs disease, which is a congenital lack of nerves in the intestines leading to bowel dysfunction. Additionally, hearing loss is not as common as in type 2. Rarely, cleft lip has been reported in this form of Waardenburg syndrome.Type 4 can also be caused by a mutation in SOX10 (the same gene as in type 2E), in which it is known as type 4C; hearing loss is very common and severe in this type. PCWH
A mutation in SOX10, the gene involved in type 2E and type 4C, can sometimes result in the symptoms of both types (neurological symptoms, as sometimes seen in type 2E, and Hirschsprungs disease, as seen in type 4). When this happens, it is called peripheral demyelinating neuropathy–central dysmyelinating leukodystrophy–Waardenburg syndrome–Hirschsprung disease (PCWH). Cause
Waardenburg syndrome is caused by mutations in any of several genes that affect the operation of neural crest cells in embryonic development. Most types of Waardenburg syndrome are caused by autosomal dominant mutations. The few that are autosomal recessive are rare. In most cases, an affected person has inherited it from one parent with one of the dominant forms of the condition. A small percentage of cases result from spontaneous new mutations in the gene, where no family history of the condition exists.The neural crest is a group of temporary migratory cells that are left over after the neural tube has closed (neurulation), around the fourth week of embryonic development.
Xanthoma planum
Xanthoma planum (ILDS D76.370), also known as plane xanthoma, is clinically characterized by bands or rectangular plates (macules) and plaques in the dermis spread diffusely over large areas of the body. : 531

Palmar xanthoma
Palmar xanthoma is clinically characterized by yellowish plaques that involve the palms and flexural surfaces of the fingers. : 531  Plane xanthomas are characterised by yellowish to orange, flat macules or slightly elevated plaques, often with a central white area which may be localised or generalised. They often arise in the skin folds, especially the palmar creases. They occur in hyperlipoproteinaemia type III and type IIA, and in association with biliary cirrhosis. The presence of palmar xanthomata, like the presence of tendinous xanthomata, is indicative of hypercholesterolaemia. Tuberoeruptive xanthoma
Tuberoeruptive xanthoma (ILDS E78.210) is clinically characterized by red papules and nodules that appear inflamed and tend to coalesce. : 532  Tuberous xanthomata are considered similar, and within the same disease spectrum as eruptive xanthomata. Other types
Other types of xanthoma identified in the Medical Dictionary include:
Xanthoma diabeticorum: a type of eruptive xanthoma, often with severe diabetes. Xanthoma disseminatum: a rare xanthoma consisting of non-X histiocytes on flexural (folded) surfaces, associated with diabetes insipidus. Verrucous xanthoma, or histiocytosis Y: a papilloma of the oral mucosa and skin whereby the connective tissue under the epithelium contains histiocytes. See also
Xanthelasma
List of xanthoma variants associated with hyperlipoproteinemia subtypes

References
External links

 Media related to xanthoma at Wikimedia Commons
MedlinePlus Encyclopedia: Xanthoma