Elevated hprt mutant frequency in circulating T-lymphocytes of xeroderma pigmentosum patients.
The mutant frequency to 6-thioguanine resistance in circulating T-lymphocytes from 10 xeroderma pigmentosum patients (including complementation groups D and G and XP variants) has been determined. A highly significantly elevated frequency was observed, compared to age-matched, non-smoking control donors (x 2.1-fold higher than the mutant frequency in normal control donors, adjusted for age and cloning efficiency, p less than 0.001). The mutant frequency of 5 XP heterozygotes was in the normal range, when age, smoking habit and log cloning efficiency were taken into account. A number of possible factors which may account for the elevated mutant frequency seen in the XP donors (including an elevated spontaneous mutation rate, UV mutagenesis of the T-cells as they pass through the skin, an effect of environmental mutagens such as tobacco smoke, or as a consequence of immune deficiency) are discussed.
Cole
J
J
MCR Cell Mutation Unit, University of Sussex, Falmer, Brighton, Great Britain.
Arlett
C F
CF
Norris
P G
PG
Stephens
G
G
Waugh
A P
AP
Beare
D M
DM
Green
M H
MH
D000328:Adult; D000368:Aged; D002648:Child; D004351:Drug Resistance / Q000235:genetics; D005260:Female; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012907:Smoking; D013601:T-Lymphocytes / Q000201:enzymology*; D013866:Thioguanine / Q000494:pharmacology; D014983:Xeroderma Pigmentosum / Q000201:enzymology / Q000235:genetics*
D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine