[DNA repair capacity measurement and possibility of heterozygote detection using nucleoid sedimentation technique among members taken from 3 xeroderma pigmentosum (XP) families].
The nucleoid sedimentation test was used to analyse the DNA repair capacity in 35 members taken from 3 xeroderma pigmentosum (XP) families after their peripheral blood lymphocytes being exposed to UV irradiation or N-methyl-N-nitro-N-nitrosoguanidine (MNNG) at a dose of 2.5 microJ/mm2 and 2 micrograms/ml respectively. The results showed that the 6 XP patients all failed to repair their damaged DNA even after 20-hour incubation at 37 degrees C. The repair ratios were 0.61 +/- 0.13 for UV and 0.44 +/- 0.15 for MNNG while those of non-related normal members usually reached 0.96 +/- 0.07 and 0.71 +/- 0.07 for both UV and MNNG after 11-hour incubation. It is interesting to note that 9 obligatory heterozygotes (parents and grandparents of XP patients) and 4 highly possible heterozygotes (blood relatives of XP patients) also showed very poor DNA repair capacity: they could not accomplish their repair process even after 20-hour incubation. It has been showed that the nucleoid sedimentation test can probably be used to pick out the heterozygotes in XP families.
Wu
D
D
Cancer Institute, Chinene Academy of Medical Sciences, Beijing.
Fu
M
M
Wang
X
X
Wu
M
M
Qiang
K
K
Huo
Z
Z
Xu
F
F
Zhao
W
W
Jiao
H
H
Dong
J
J
D000293:Adolescent; D002467:Cell Nucleus; D002648:Child; D004260:DNA Repair; D005192:Family Health; D005260:Female; D006580:Genetic Carrier Screening / Q000379:methods; D006801:Humans; D008297:Male; D014983:Xeroderma Pigmentosum / Q000235:genetics* / Q000473:pathology