Abstract: Objective To investigate the association of XRCC1-Arg399Gln polymorphism with hyroid-tassociated ophthalmopathy (TAO ) . Methods XRCC1-Arg399Gln polymorphism was determined by PCR-RFLP in 182 patients with TAO and 182 healthy subjects. Results The significant difference of the allelic frequency distribution was found between TAO and control group（P〈0.001）,The frequency of A allelic in TAO was higher than that in control group .Compared with subjects carrying GG allele, the risk of TAO for the individuals carrying GA+AA allele increased（OR 1.863，95%CI 1.228~2.826，P＜0.05）. The OR of TAO for individuals carrying A allele or cigarette smokers was respectively 1.343(95%CI 0.764~2.36) and 2.0274(95%CI 1.121~3.667).But The combination of the above two made the OR of TAO up to 4.981(95%CI 2.697~9.1998). Conclusion Allele A in XRCC1Arg399G1n may be associated with TAO. Potential interactions were found among XRCC1-Arg399G1n polymorphisms and cigarette smoking.

Key words: thyroid-associated ophthalmopathy (TAO ), XRCC1, genetic polymorphism