Dr. Kenneth H. Kraemer, research dermatologist at the National Cancer Institute in Bethesda, says patients with the disease have a thousandfold increase in their chances of getting skin cancer compared to the average person. The first skin cancer may develop before a person is 10 years old, and many other skin cancers may occur in the future.

Xeroderma Pigmentosum Society (www.xps.org) is a nonprofit organization that sponsors Camp Sundown, a nighttime camp held in the summer that is open to xeroderma pigmentosum patients and their families. Sufferers of other light-sensitive conditions also are welcome.