DNA repair gene polymorphisms, pre-natal factors and the frequency of somatic mutations in the glycophorin-A gene among healthy newborns.
This study investigates variation in somatic mutation frequency, as measured by the glycophorin-A (GPA) somatic mutation assay, in relation to polymorphic variation among 435 newborn babies in DNA repair genes XRCC1, XRCC3 and XRCC4 and gender, parental age, social class and smoking habits. The three polymorphisms under investigation were an Arg --> Gln substitution at codon 399 in exon 10 of XRCC1, a Thr --> Met substitution at codon 241 in exon 7 of XRCC3 and an Ile --> Thr substitution at codon 401 in exon 4 of XRCC4. The study population is an extension of that previously analysed for GPA mutations and XRCC1 polymorphisms. A significant difference was seen in the earlier work in the genotype distribution for the XRCC1 Arg399Gln polymorphism between the main population and the small number with extreme values for NN variant frequency and this was maintained in the larger study group (OR 3.20 [95% CI: 1.16, 8.81]) P = 0.043). No such association was seen for XRCC3 or XRCC4 polymorphisms. When adjustments were made for multiple testing, neither N0 nor NN variant frequencies in the main study population were found to be influenced by the polymorphisms in XRCC1, XRCC3, or XRCC4. In addition, neither maternal or paternal smoking, age or social class nor the gender of the offspring were found to affect variant frequencies nor were variant frequencies influenced by any interaction between any of these factors and genotype. It is concluded that the genotypic variation in DNA repair genes examined in this study has no discernable effect on the genesis of the somatic mutations observed at birth.
Relton
Caroline L
CL
Genetics Unit, Westlakes Research Institute, Moor Row, Cumbria CA24 3JY, UK. carolin.relton@westlakes.ac.uk
Daniel
C Paul
CP
Hammal
Donna M
DM
Parker
Louise
L
Janet Tawn
E
E
Burn
John
J
D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D005312:Fetal Blood; D005838:Genotype; D006021:Glycophorins / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D007231:Infant, Newborn; D009154:Mutation; D011110:Polymorphism, Genetic; D012044:Regression Analysis; D000076105:X-ray Repair Cross Complementing Protein 1
D004268:DNA-Binding Proteins; D006021:Glycophorins; D000076105:X-ray Repair Cross Complementing Protein 1; C110901:X-ray repair cross complementing protein 3; C000619371:XRCC1 protein, human; C101467:XRCC4 protein, human