Xeroderma pigmentosa

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Chromosomes and DNA

Xeroderma pigmentosa is an inherited inability of the skin to repair DNA damage from ultraviolet light.

Xeroderma pigmentosa is inherited as an autosomal recessive trait. Those affected are extremely sensitive to the ultraviolet portion of sunlight. Ultraviolet light exposure damages DNA (the genetic material within a cell) in skin cells.

Normally, peoples' bodies can repair this damage. However, people with xeroderma pigmentosa cannot repair the damaged DNA and rapidly develop skin atrophy (thinning), splotchy pigmentation, spidery blood vessels in the skin (telangiectasia), and skin cancers.

Skin cancers include basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. Basal cell skin cancers are fairly easy to treat and have a low rate of metastasis. Squamous cell cancer is more difficult to treat, and melanoma has a very high rate of spreading to other organs.

Affected people develop increasing disfigurement following any intermittent exposure to sunlight. Malignant (cancerous) skin lesions are often present before the child is 5 years old.

Review Date: 04/30/2005
Reviewed By: Jonathan Kantor, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.