Objective   To investigate the relationships between polymorphisms of X-ray repair cross complementing group 1(XRCC1)A194W and A399Q and susceptibility to lead poisoning and to find the biomarkers of susceptibility to lead poising.

  Methods   A case-control study was performed among 122 patients diagnosed with lead poisoning and 142 diseasefree controls.The genotypes of participants in two groups were detected by PCR-restriction fragment length polymorphisms (PCR-RFLP)methods and the effects of different genotypes on susceptibility to lead poisoning were investigated.

  Results   The distributions of the mild genotype, heterozygous mutation genotype and homozyg ous mutation genotype of XRCC1 A194W and A399Q polymorphism between lead poisoning group and control group were significantly different(P < 0.05).In XRCC1 A194W polymorphism, heterozygous mutation genotype(CT), homozy gousmutation genotype(TT)and mutation genotype(CT+TT)could increase 2.03-fold, 2.59-fold and 2.12-fold risk of lead poisoning compared with mild genotype(CC), respectively.In XRCC1 A399Q poly morphism, there were 0.37-fold and 0.52-fold decreased risk of lead poisoning in heterozygous mutation genotype(GA)and mutation genotype(GA+AA)compared with wild genotype(GG), respectively.The homozygous mutation genotype(AA)might not relate to risk of lead poisoning.

  Conclusion   The polymorphisms of XRCC1 A194W and A399Q contribute to susceptibility to lead poisoning, which may be suggested as important biomarkers of susceptibility to lead poisoning.