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xeroderma pigmentosum
xeroderma pig·men·to·sum X0005250 (pĭg′mən-tō′səm)n. A rare hereditary skin disorder caused by a defect in the enzymes that repair DNA damaged by ultraviolet light.
[New Latin xēroderma pigmentōsum : xēroderma, xeroderma + pigmentōsum, neuter of pigmentōsus, of pigment.]Thesaurus| Noun | 1. | xeroderma pigmentosum - a rare genetic condition characterized by an eruption of exposed skin occurring in childhood and photosensitivity with severe sunburn; inherited as a recessive autosomal trait in which DNA repair processes are defective so they are more likely to chromosome breaks and cancers when exposed to ultraviolet lightxeroderma, xerodermia - a mild form of ichthyosis characterized by abnormal dryness and roughness of the skin |
Xeroderma Pigmentosum
xeroderma pigmentosum[‚zir·ə′dər·mə ‚pig·mən′tō·səm] (medicine) A genodermatosis characterized by premature degenerative changes in the form of keratoses, malignant epitheliomatosis, and hyper- and hypopigmentation. Xeroderma Pigmentosum a chronic congenital disease of the skin, first described by the Austrian physician M. Kaposi in 1870. Xeroderma pigmentosum is a hereditary disease (a recessive genodermatosis) often found in children whose parents are blood relatives. The disease begins in early childhood (at age two or three) with an increased sensitivity of the skin to ultraviolet rays. In the spring, reddish spots (to the size of a bean) appear on the exposed areas of the body (face, neck, hands, forearms, legs, and feet). These later acquire a yellowish brown tint, resembling freckles. The affected skin gradually becomes dry. Small scales form on its surface, sometimes accompanied by cracks and a purulent crust (a result of associated secondary infection). The skin in the affected areas subsequently becomes thin and begins to wrinkle. Distended blood vessels appear on its surface (telangiectases). Depigmented areas appear along with the pigmented spots. Often, warty growths appear around the nidi; these may degenerate into basal-cellular or spino-cellular epitheliomas. For this reason, xeroderma pigmentosum is regarded as a precancerous disease. The treatment of xeroderma pigmentosum is directed mainly against the tumorous and ulcerous formations, using corticosteroids, short-focus X-ray therapy, electric coagulation, and surgical intervention. Photodesensitizing preparations, photo-protective creams (containing 10 percent phenyl salicylate and 5 percent quinine), and the salve Fotonem are helpful in preventing appearances of the condition. Exposure to the sun should be avoided (especially during the spring and summer). Regular checkups are recommended. I. IA. SHAKHMEISTER xeroderma pigmentosum
xeroderma [ze″ro-der´mah] excessive dryness of the skin, a mild form of ichthyosis.xeroderma pigmento´sum a rare and often fatal pigmentary and atrophic disease in which the skin and eyes are extremely sensitive to light. It begins in childhood and progresses to early development of excessive freckling, telangiectases, keratoses, papillomas, carcinoma, and melanoma. Ocular symptoms include photophobia, opacities, and tumors. It is inherited as an autosomal recessive trait involving a defect in the enzymes active in the repair of DNA damaged by ultraviolet irradiation. Subtypes of this disorder have been identified by the capacity for DNA repair. Total protection from sunlight prevents the development of lesions.xe·ro·der·ma pig·men·to·'sum [MIM*278700] an eruption of exposed skin occurring in childhood and characterized by photosensitivity with severe sunburn in infancy and the development of numerous pigmented spots resembling freckles, larger atrophic lesions eventually resulting in glossy white thinning of the skin surrounded by telangiectases, and multiple solar keratoses that undergo malignant change at an early age; results from several rare autosomal recessive complementation groups in which DNA repair processes are defective, so that they are more liable to chromosome breaks and cancerous change when exposed to ultraviolet light. Severe ophthalmic and neurologic abnormalities are also found.
See also: De Sanctis-Cacchione syndrome. xeroderma pigmentosum (pĭg′mən-tō′səm)n. A rare hereditary skin disorder caused by a defect in the enzymes that repair DNA damaged by ultraviolet light.xe·ro·der·ma pig·men·to·sum (zērō-dĕrmă pigmen-tōsŭm) An eruption of exposed skin occurring in childhood and characterized by photosensitivity with severe sunburn in infancy and the development of numerous pigmented spots resembling freckles, larger atrophic lesions eventually resulting in glossy white thinning of the skin surrounded by telangiectases, and multiple solar keratoses that undergo malignant change at an early age. Severe ophthalmic and neurologic abnormalities are also found. xeroderma pigmentosum A group of rare AUTOSOMAL RECESSIVE genetic skin diseases featuring excessive sensitivity to sunlight, which causes premature ageing of the skin, PIGMENTATION and the development of skin cancers. Victims are condemned to an almost wholly indoor existence and have to use protective coverings and skin sunscreen creams out of doors.xeroderma pigmentosum a lethal genetical disorder of the skin in which affected individuals exhibit unusually heavy freckling and ulceration of the skin that has been exposed to sunlight. Such individuals lack an endonuclease enzyme that normally repairs thymine DIMERS produced in DNA by ultraviolet light. Affected individuals are thought to be homozygous for a pair of recessive alleles on an AUTOSOME, although there may be up to five different genes involved in the condition. Heterozygous individuals are often heavily freckled. There is no treatment and death usually occurs in childhood.xeroderma pigmentosum An autosomal recessive inherited disease in which there is progressive pigmentary degeneration of the skin, especially in sun-exposed areas. It results from a deficient enzyme used in the repair of DNA damaged by ultraviolet light. The condition begins in infancy and is characterized by the appearance of numerous pigmented spots resembling freckles and telangiectases. Eventually atrophic patches appear as well as wart-like excrescence and often squamous cell carcinoma. Patients are photophobic and the eyelids are frequently affected with atrophy and ectropion, which may be accompanied with conjunctival inflammation and corneal ulceration. Protection of the eyes and skin is essential as well as surgical removal of the carcinomatous tumours, but many patients eventually succumb to metastases.xe·ro·der·ma pig·men·to·sum (zērō-dĕrmă pigmen-tōsŭm) [MIM*278700] Eruption of exposed skin occurring in childhood and characterized by photosensitivity with severe sunburn in infancy and the development of numerous pigmented spots resembling freckles, larger atrophic lesions eventually resulting in glossy white thinning of the skin surrounded by telangiectases, and multiple solar keratoses that undergo malignant change at an early age. AcronymsSeeexophoriaxeroderma pigmentosum
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