Amyloidosis cutis dyschromica. DNA repair reduction in the cellular response to UV light.
BACKGROUND
Amyloidosis cutis dyschromica, a special type of primary cutaneous amyloidosis, is assumed to be a congenital disorder and sun exposure is thought to be the major causal factor. Herein we report a case of this rare disease and DNA repair characteristics of UV damages in the fibroblasts derived from the patient.


METHODS
A 24-year-old Japanese woman showed hyperpigmented and hypopigmented xerotic lesions in sun-exposed skin since she was 10 years old; deposits of amyloid material were detected in the papillary dermis. The fibroblasts were hypersensitive to UV-B, but not so sensitive to UV-C. Unscheduled DNA synthesis of the patient's cells after UV-C exposure was lower than that of normal cells at 3 hours and both reached the same level at 6 hours. After UV-B exposure, unscheduled DNA synthesis of the patient's cells was lower than that of normal cells at least until 6 hours after UV exposure.


CONCLUSIONS
Although the origin of amyloidosis cutis dyschromica is unknown, hypersensitivity to UV-B with possible DNA repair defects is suggested to be the cause of this disease.
Moriwaki
S
S
Department of Dermatology, Faculty of Medicine, Kyoto University, Japan.
Nishigori
C
C
Horiguchi
Y
Y
Imamura
S
S
Toda
K
K
Takebe
H
H
D000328:Adult; D000686:Amyloidosis / Q000209:etiology* / Q000473:pathology; D003114:Colony-Forming Units Assay; D004247:DNA / Q000096:biosynthesis; D004260:DNA Repair / Q000528:radiation effects; D005260:Female; D005347:Fibroblasts / Q000528:radiation effects / Q000648:ultrastructure; D006801:Humans; D010787:Photosensitivity Disorders / Q000150:complications* / Q000473:pathology; D012867:Skin / Q000166:cytology / Q000473:pathology*; D014466:Ultraviolet Rays
D004247:DNA