Purpose
It was reported that a genetic variant of collagen, type XV, alpha 1 (COL15A1) gene, R163H, influenced the age of onset in Caucasian and African-American patients with high tension glaucoma (HTG); primary open-angle glaucoma (POAG) with elevated intraocular pressure (IOP). This study was performed to assess the association between this genetic variant and the phenotypic features in Japanese patients with POAG, including normal tension glaucoma (NTG) and HTG.
Methods
Five hundred and three Japanese patients with POAG, including 255 patients with NTG (63.5 ± 13.3 years, mean±standard deviation) and 248 patients with HTG (63.6 ± 14.3 years), and 236 control subjects without glaucoma (67.8 ± 11.1 years) were analyzed for COL15A1 genetic variant, R163H (rs2075662). The genotype and allele frequencies were compared between the patients with NTG or HTG and the control subjects. Demographic and clinical features, including the age at diagnosis of glaucoma, gender, family history of glaucoma, refractive error, maximum IOP, vertical cup-to-disc ratio, and history of glaucoma surgery, were compared between the genotypes in patients with POAG. A multiple linear regression analysis was carried out with the age at diagnosis of glaucoma as a dependent variable and gender, refractive error, maximum IOP, and the genetic variant as independent variables.
Results
There were no significant differences of the genotype and allele frequencies between the patients with NTG (AA: 8.6%, AG: 43.5%, GG: 47.9%, P=0.90; A allele: 30.4%, G allele: 69.6%, P=0.89) or HTG (AA: 5.7%, AG: 40.3%, GG: 54.0%, P=0.16; A allele: 25.8%, G allele: 74.2%, P=0.09) and the control subjects (AA: 9.7%, AG: 42.4%, GG: 47.9%; A allele: 30.9%, G allele: 69.1%). No significant differences of the phenotypic features were found among the genotypes, including the age at diagnosis of glaucoma (AA: 55.2 ± 13.8 years, AG: 57.0 ± 13.6 years, GG: 56.6 ± 14.3 years, P=0.76), in patients with POAG. Based on multiple linear regression analysis, a significant relationship was not also found between the genetic variant and the age at diagnosis of glaucoma (β = 0.014, standard error = 0.87, P = 0.72).
Conclusions
The association between the COL15A1 R163H genetic variant and the phenotypic features, including the age at diagnosis of glaucoma was not found in Japanese patients with POAG.