Purpose.Ultraviolet irradiation i s known to cause oxidative DNA damage and is thought to be a major factor implicated in the pathogenesis of pterygium.The highly mutagenic 8-hydroxy -2-deoxyguanosine,a marker for the evaluation of photo-oxidative DNA damage,can be r epaired by human 8-oxoguanine glycosylase I (hOGG1).A transition of C to G at nucleotide position 1245in exon 7of the hOGG1gene is associated with the substitution of cysteine for serine at codon 326.In this study,we investig ated the association of the hOGG1Ser326Cys polymorphism wi th pterygium in a Chinese population.Methods.In all,70patients and 86controls were enrolled in this study.The Ser326Cys poly-morphism was determined by the polym erase chain reac-tion-restriction fragment-length polymorphism analysis.The association between this genetic polymorphism and risk of pterygium was examined byχ 2 -test and logistic regression.Results.The allelic frequencies fo r the Ser and Cys vari-ants of hOGG1gene were not significa ntly different between the two groups.However,when compared with Ser /Ser and Ser /Cys genotypes combined,we f ound that the ho-mozygous Cys /Cys genotype was more p revalent in ptery-gium patients than controls(P=0.024)with the odds ratio being 2.2(95%CI:1.1-4.5).In the pterygium group,the mean age of patients with t he Cys /Cys geno-typewas younger than those with the o ther two genotypes(P=0.025).Conclusions.Our findings suggest that the1245C→G transition in exon 7of the hOGG1gen e,which results in Ser326Cys substitution o f the enzyme,might play a role in the susceptibility of human s to pterygium. Purpose. Ultraviolet irradiation is known to cause oxidative DNA damage and is thought to be a major factor implicated in the pathogenesis of pterygium. The highly mutagenic 8-hydroxy-2-deoxyguanosine, a marker for the evaluation of photo-oxidative DNA damage, can be r epaired by human 8-oxoguanine glycosylase I (hOGG1). A transition of C to G at nucleotide position 1245 in exon 7 of the hOGG1 gene is associated with the substitution of cysteine ​​for serine at codon 326. In this study, we investigated ated the association of the hOGG1Ser326Cys polymorphism wi th pterygium in a Chinese population. Methods. All all, 70patients and 86controls were enrolled in this study.The Ser326Cys poly-morphism was determined by the polym erase chain reac tion-restriction fragment-length polymorphism analysis. association between this genetic polymorphism and risk of pterygium was examined byχ 2 -test and logistic regression. Results. The allelic frequencies fo r the Ser and Cys vari-ants of hOGG1 gene were not signif Wently different between the two groups. Despite, when compared with Ser / Ser and Ser / Cys genotypes combined, we f ound that the ho-mozygous Cys / Cys genotype was more revalent in ptery-gium patients than controls (P = 0.024 ) with the odds ratio being 2.2 (95% CI: 1.1-4.5) .In the pterygium group, the mean age of patients with t Cys / Cys geno-type was younger than those with the o ther two genotypes (P = 0.025) .Conclusions.Our findings suggest that the 1245C → G transition in exon 7 of the hOGG1gen e, which results in Ser326Cys substitution of the enzyme, might play a role in the susceptibility of human s to pterygium.