Enhanced chromatid damage in blood lymphocytes after G2 phase x irradiation, a marker of the ataxia-telangiectasia gene.
An assay for ataxia-telangiectasia (A-T) heterozygotes, i.e., healthy carriers of the A-T gene(s), requiring only a small sample (3.5 mL) of peripheral blood, is described. Frequencies of chromatid aberrations in phytohemagglutinin-stimulated blood lymphocytes collected by demecolcine from 0.5 hour to 1.5 hours after x irradiation with 58 roentgens were twofold to threefold higher in A-T heterozygotes than in clinically normal controls and twofold to three-fold higher in A-T patients (homozygotes) than in A-T gene carriers. The persistence of chromatid breaks and gaps in lymphocytes following radiation-induced DNA damage during G2 suggests a deficiency or deficiencies in DNA repair that may be the defect at the molecular level that results in the enhanced radiosensitivity and cancer proneness characterizing A-T gene carriers and patients.
Sanford
K K
KK
Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Parshad
R
R
Price
F M
FM
Jones
G M
GM
Tarone
R E
RE
Eierman
L
L
Hale
P
P
Waldmann
T A
TA
D000293:Adolescent; D000328:Adult; D000368:Aged; D001260:Ataxia Telangiectasia / Q000235:genetics*; D002648:Child; D002842:Chromatids / Q000528:radiation effects*; D004249:DNA Damage; D005260:Female; D006579:Heterozygote; D006801:Humans; D007399:Interphase / Q000528:radiation effects*; D008214:Lymphocytes / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D011836:Radiation Tolerance