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, TTD, XP/TTD and other overlap syndromes to follow their clinical
course. We will obtain tissue (skin, blood, hair, buccal cells) 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:

- On referral, subjects will be considered for inclusion in the study:

If they have clinical documentation of typical features of XP, XP/CS, CS or TTD, XP/TTD or
other overlap syndromes or

If they have laboratory documentation of defective DNA repair or

If they have some suggestive clinical features and are willing to participate in the study
or

if they are first degree relatives or other family members of patients with XP, XP/CS, CS,
TTD, XP/TTD or other overlap syndromes

if they are healthy volunteers (including NIH employees) willing to donate blood, skin,
buccal cells, or hair.

- Pregnant women may be included in the study, but will not receive X-ray, CT, or MRI
testing, unless medically indicated, because of possible risks to the fetus

- 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.