This study will determine if family members of patients with xeroderma pigmentosum (XP) have various abnormalities, including: skin abnormalities; nervous system abnormalities, such as hearing problems; skin, eye, or internal cancers, or other changes. XP is a rare inherited disease that involves an inability to repair damage to cell DNA (genetic material). It can affect several organ systems, including the skin, eye, nervous system, and bones. Patients have a more than thousand-fold increase in frequency in all major skin cancers.