Examination of Clinical and Laboratory Abnormalities in Patients With Defective DNA Repair: Xeroderma Pigmentosum, Cockayne Syndrome, or Trichothiodystrophy

Four rare genetic diseases, xeroderma pigmentosum (XP), Cockayne syndrome (CS), the XP/CS complex and trichothiodystrophy (TTD) have defective DNA excision repair although only XP has increased cancer susceptibility. We plan to perform careful clinical examination of selected patients with XP, XP/CS, CS, or TTD and follow their clinical course. We will obtain tissue (skin, blood, hair, buccal swabs) for laboratory examination of DNA repair and for genetic analysis. We hope to be able to correlate these laboratory abnormalities with the clinical features to better understand the mechanism of cancer prevention by DNA repair. Patients will be offered counseling and education for cancer control.

* INCLUSION CRITERIA: * Subjects age 6 weeks and above: * with clinical and/or laboratory documentation of typical features or suggestive clinical features of XP, CS, TTD, or overlap syndromes or * that are first degree relatives or other family members of participants with XP, CS, TTD, or overlap syndromes * Healthy volunteers of age 1 year and above (including NIH employees) willing to donate blood, skin, buccal cells, or hair. * Patients or legally authorized representatives must provide informed consent. EXCLUSION CRITERIA: -Inability or unwillingness to provide tissue (skin, blood, buccal cells or hair) for laboratory studies.