What is piebaldism?Piebaldism is a rare medical condition characterized by a white forelock and hypopigmented patches of skin.
Nearly 90% of the piebaldism affected individuals have white forelocks. Apart from forelocks, eyebrows, eyelashes and the skin beneath the forelock may also lack pigmentation. In some individuals irregularly shaped white patches have been observed on the face, trunk and extremities. These hypopigmentation patches are mostly found to have symmetrical distribution. Some piebaldism affected individuals may not develop white forelocks and in some persons white forelocks are the only signs of piebaldism.
Signs and symptoms of piebaldismSome of the signs and symptoms are:
- presence of non pigmented patches of skin at birth
- hypopigmented patches are non-progressive and do not increase in size or number
- White forelock
- unpigmented skin beneath the forelock
- white eyebrows and eyelashes
- symmetrical non pigmented patches on the face and body
- narrow border of hyperpigmented skin surrounding the patches
- islands of normal or hyperpigmented skin inside the hypopigmented patches
What are the causes of piebaldism?
- Piebaldism is caused by mutations in the KIT and SNAI2 genes. The mutations may be as deletions, nucleotide splice mutations or insertions. Individuals affected by Waardenburg syndrome may also develop the symptoms of piebaldism. The effects of mutations lead to defective melanoblasts proliferation, decreased survival and defective migration from the neural crest during development.
- KIT gene (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog)
The KIT gene is responsible for the synthesis of KIT proteins required for cell signaling. KIT protein signaling is important for cell proliferation, cell migration and development of hematopoietic stem cells, mast cells, interstitial cells of Cajal and reproductive cells.
KIT protein signaling is also essential for melanocyte development. Mutations in KIT gene lead to nonfunctional KIT protein affecting the proliferation and migration of the precursor cells (melanoblasts) of the melanocytes. The location of mutation within the KIT gene correlates with phenotypic expression in piebaldism. More than 69 KIT gene mutations have been identified.
- SNAI2 gene (snail family zinc finger 2)
- The SNAI2 gene is involved in the production of snail 2 protein. The precursor cells of melanocytes are formed from neural crest cells during embryonic development. The development of neural crest cells and their migration and transformation is signaled by snail 2 protein. The formation melanoblasts and their transformation into melanocytes is probably brought about snail 2 protein. Any mutation in SNAI2 gene may affect the melanocyte formation and cause patches of unpigmented skin and piebaldism.
Difference between piebaldism and Waardenburg syndrome
A few of the piebaldism affected individuals may have normal hearing. Sometimes the eyes may be differently colored. White patches of skin and hair may be present. Waardenburg syndrome is caused by mutations in EDN3, EDNRB, MITF, PAX3, SNAI2, and SOX10 genes. There are four types of this disorder, and type II Waardenburg syndrome is caused by mutations in the MITF and SNAI2 genes.
Differences between piebaldism, vitiligo and albinism
- Vitiligo and piebaldism are characterized by white hypomelanosis patches of skin totally lacking skin pigment. In albinism there is total inability of skin to produce skin melanin.
- Vitiligo is an acquired medical condition in which depigmented patches arise on normal colored skin. Vitiligo is an autoimmune disease wherein the body's immune mechanism destroys the melanocytes. Piebaldism and albinism are congenital disorders and are present at birth.
- In albinism hair and skin are completely without skin pigment. In piebaldism, the patches are static and do not increase in size or number. Vitiligo can spreads progressively all over the body.
- In 80-90% of cases of piebaldism, there is white forelock and triangular hypopigmentation of the skin beneath it. In vitiligo there may facial pigment loss and it may appear on the forelock also. But the typical triangular hypopigmentation is absent.
- Albinos lack pigment in their eyes and have visual impairment. The nature and degree of their visual impairment may vary significantly. Persons with piebaldism or vitiligo usually have normal vision.
Piebaldism treatment and managementThe unpigmented skin is unresponsive to medical treatment and light therapy. Long exposure to sunlight or UV light may cause inflammation, sunburn or cutaneous malignancy. Piebaldism affected persons are advised to use sun protective measures. If the patches are small, cosmetic camouflage makeup may be applied.
Piebaldism treatments include dermabrasion and split-skin grafting. The split-skin grafting treatment followed by minigrafting treatment gives appreciable results. Autologous cultured epidermis graft treatment has been found to induce permanent repigmentation of large achromic lesions. In this non-invasive surgical treatment nearly 95% repigmentation is achieved. Before the treatment the non pigmented epidermis is removed with erbium:YAG laser.
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Genetics Home Reference, National Institutes of Health
4.Piebaldism treatment: Guerra, L., Primavera, G., Raskovic, D., Pellegrini, G., Golisano, O., Bondanza, S., Kuhn, S., Piazza, P., Luci, A., Atzori, F. and De Luca, M. (2004), Permanent repigmentation of piebaldism by erbium:YAG laser and autologous cultured epidermis. British Journal of Dermatology, 150: 715–721.
Current topic on natural skin care:
Piebaldism causes, symptoms and treatment.