xeroderma pigmentosum

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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.

xeroderma pigmentosum (XP)

a rare, inherited skin disease resulting from faulty DNA repair, characterized by extreme sensitivity to ultraviolet light, exposure to which results in freckles, telangiectases, keratoses, papillomas, carcinoma, and, possibly, melanoma. Keratitis and tumors developing on the eyelids and cornea may result in blindness. Exposure to sunlight must be avoided. See also Kaposi's disease.
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Xeroderma pigmentosum

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

autosomal-recessive disorder characterized by hypersensitivity to ultraviolet light; characterized by numerous small, pigmented, freckle-like macules, larger areas of white, glossy atrophic skin surrounded by telangiectasias and multiple solar keratoses (note: subject to malignant change)

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.