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XP/TTD patients with XPD gene defects have clinical features of Xeroderma Pigmentosum and Trichothiodystrophy

Thursday, October 11, 2012 — Poster Session III

10:00 a.m. – Noon

Natcher Conference Center, Building 45




  • S. G. Khan
  • D. Tamura
  • T. Rao
  • W. Zein
  • B. Brooks
  • J. Boyle
  • T. Ueda
  • J. J. DiGiovanna
  • K. H. Kraemer


Mutations in the XPD DNA repair gene cause the rare autosomal recessive genetic diseases: trichothiodystrophy (TTD) and xeroderma pigmentosum (XP). XP patients have a 10,000-fold increased skin cancer risk, while TTD patients have a spectrum of clinical manifestations but no skin cancer. We describe 5 patients (3 families) with compound heterozygous mutations in XPD and features of both TTD and XP. All had acute burning on minimal sun exposure, freckle-like pigmentation on sun-exposed skin, cataracts, and tiger-tail banding of the hair shafts under polarized light. Three sisters in family 1 had skin cancer, and one died of metastatic melanoma with unknown primary at age 32. An 18 y/o female in family 2 had a large anaplastic hemangiopericytoma of the brain at age 17. A 55 y/o male in family 3 had a total of 25 skin cancers including 5 melanomas with metastasis to his parotid glands. XP/TTD patients have clinical features of both XP and TTD and are at increased risk for skin as well as internal cancers. Each XPD mutation might affect different functions of the basal transcription factor TFIIH, and thus the combination of mutations may be critical for distinct clinical features in these patients.

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