The journal of Dermatology Vol. 19: 690-695, 1992

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Xeroderma Pigmentosum: Recent Clinical and Photobiological Aspects Seiji Kondo*, Shuhei Fukuro*, Kiyoshi Nishioka* and Yoshiaki Satoh*,** Abstract

In Japan, more than 400 patients with xeroderma pigmentosum (XP) have been registered. The major groups are XP-A and variant, while clinically mild types ofXP with intermediate levels of unscheduled DNA synthesis (UDS) have recently been increasing. The classical type of XP-A and some of the XP-D patients exhibit neurologic abnormalities. XP individuals display a marked increase in the frequency of skin malignancy. Development of skin malignancies appears to be related to the level of DNA repair capacity; the lower the capacity, the earlier and more frequently the skin tumors develop. Furthermore, the incidence of internal malignancy in XP patients is at least ten times higher than that for the Japanese general population over the age of 40 years. Cultured fibroblasts from XP patients exhibit higher sensitivity not only to WC but also to UVB. The cellular sensitivity to UVB may correlate to photosensitivity in vivo from a study on a group E patient who showed age-related changes in photosensitivity and cellular sensitivity to UVB. We have also reviewed current status of molecular genetics in XP.

Key words: vitamin D

xeroderma pigmentosum; carcinogenesis; DNA repair; neurologic involvement;

Introduction

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease characterized by extreme photosensitivity and neurologic abnormalities (1). It is also well known that XP patients have a high incidence of cutaneous malignancies and that XP cells are inefficient in the repair of W-induced DNA damage (1). Therefore, many investigators have tried to elucidate the role of DNA repair in the mechanism of carcinogenesis. At present, XP is known to comprise at least 7 excision-defective complementation groups (A through G) and an excision-proficient variant group. Group H and I cases have been reassigned to groups D (2) and C (3), respectively. Here we report a clinical and photobiological study ofJapanese XP patients and review current topics in XP. *Department of Dermatology, School of Medicine, Tokyo Medical and Dental University, Tokyo,japan. **Department of Dermatology, Tokyo Women's Medical College, Dai-Ni Hospital, Tokyo,japan. Reprint requests to: Dr. Seiji Kondo, Department of Dermatology, School of Medicine, Tokyo Medical and Dental University, 5-45, Yushima I

Xeroderma pigmentosum: recent clinical and photobiological aspects.

In Japan, more than 400 patients with xeroderma pigmentosum (XP) have been registered. The major groups are XP-A and variant, while clinically mild ty...
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