Development of Primary Open-Angle Glaucoma and Deletion Polymorphism of the Glutathione-S-Transferase Genes

Abstract

The aim of the research. To investigate the association of the development of primary open-angle glaucoma with deletion polymorphism of glutathione-S-transferase genes. Materials and methods. Under our observation there were 172 patients, residents of Ukraine with primary open-angle glaucoma I–IV stages. Analysis of the deletion polymorphism of GSTM1 and GSTT1 genes was performed by real-time polymerase chain reaction using unified TaqMan Mutation Detection Assays Life-Technology (USA) test systems. Statistical analysis of the obtained data was performed using the MedStat package and the statistical package MedCalc v.15.1 (MedCalc Software bvba). Results and discussion. The detection of null alleles of the GSTM1 gene was observed in 39 % of patients in the control group, in patients with POAG a significant increase in the frequency of deletion polymorphism to 50–56 % was observed with the progression of the disease in stages II-IV. In patients with stage IV disease, the effect of the zero GSTM1- null allele on POAG course was determined (χ2=3.97; p=0.047), and the null allele of GSTM1 doubled the probability of developing the disease (OR=2.01; 95 % CI=1.01–4.01) in patients of group 4 compared with control. The null allele of the GSTT1 gene in the control group was found in 31 %, an increase in the frequency of the GSTT1-null allele was also observed in the second and fourth stages of POAG from 41 % to 54 %. Statistically significant differences of GSTT1 gene allele frequencies were determined between the control group and all patients with POAG (χ2=4.43; p=0.03), between the control and the 4th group (χ2=7.64; p=0.01), and between the 1st and 4th groups (χ2=5.52; p=0.02). An association with the development of POAG (χ2=4.43; p=0.03) was determined for the deletion polymorphism of the GSTT1 gene when comparing the control group with the data of all patients with POAG (1–4 groups). At stratification by stages of POAG (that is, by groups of patients), an association with the development of POAG was determined only in patients of group 4 (χ2=7.64; p=0.01) compared with the control group. Conclusions. The association of the null allele of the GSTT1 gene with POAG was established (p=0.03). The presence of the GSTT1-null allele significantly increased the risk of developing POAG (OR=1.75; BI=1.04–2.96) compared with the control group. The presence of null alleles (GSTM1-null and GSTT1-null) of the GST deletion polymorphism significantly increased the risk of stage IV POAG (OR=2.01; BI=1.01–4.01 and OR=2.66; VI=1.32–5.37, respectively) compared with the control group, which indicated the effect of zero alleles on the rapid progression of the disease.