Null type of glutathione S-transferase M1 polymorphism is associated with early onset pterygium

Purpose: To investigate the association of glutathione S-transferase M1 (GSTM1) null genotype with pterygium. Methods: One hundred and twenty seven pterygium patients and 102 volunteers without pterygium were enrolled in this study. Polymerase chain reaction based analysis was used to resolve the GSTM1 null and positive genotypes. Results: There was no significant difference between total pterygium and the control group. When stratified by the age, there was a significantly higher frequency of the GSTM1 null genotype in younger patients. The difference was not significant between patients and controls older than 60 years old. Conclusions: These results indicate GSTM1 null genotype is associated with early onset pterygium, but not associated with late onset pterygium.