Abstract
Purpose:
Several single nucleotide polymorphisms (SNPs) located in the CDKN2B-AS1 gene have been detected as marker SNPs for primary open-angle glaucoma, and especially for normal tension glaucoma. However, even in normal subjects, the risk allele for CDK2B-AS1 exists in approximately 80% of them. The purpose of this study was to evaluate the clinical ophthalmic data differences according to genotype data of CDKN-2BAS1 in normal subjects.
Methods:
This study involved 974 normal subjects (357 males, 617 females; mean age: 56.5±14.0 years) diagnosed as normal by glaucoma specialists after several ophthalmic examinations including optic disc photograph and visual field testing, and who had no familial history of glaucoma as determined by Affymetrix® 500K or 1000K microarray (Affymetrix, Inc., Santa Clara, CA) analysis. Of the 5 detected SNPs of CDKN2B-AS1, rs7865618 was selected as the representative SNP for statistical analysis. For clinical data, patient height, age, intraocular pressure (IOP), refractive error (RE), corneal radius (CR), axial length, optic disc area (DA), optic rim area (RA), central cornea thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA) were statistically analyzed in regard to the genotype of rs7865618 (AA/AG/GG). DA and RA were measured by retinal tomography (HRT-II; Heidelberg Engineering GmbH, Heidelberg, Germany) and data were selected RE -12D<+12D, SD <50. RE, CR , ACD, ACV, ACA were selected for both phakic eyes. ACD/ACV/ACA was measured by Pentacam® (OCULUS Optikgeräte GmbH, Wetzlar, Germany). If data was available for both eyes, the subject’s right-eye data was selected. Statistical analysis was performed by use of one-way analysis of variance (ANOVA).
Results:
The number of subjects with the AA, AG, and GG genotypes were 669, 276, and 29, respectively. No significant difference in mean age was found among the genotype groups. Patient height, CCT, DA, IOP, and RE were smaller in the GG group subjects than in the AA and AG groups subjects, however, IOP was significantly smaller than in the other two groups of subjects.
Conclusions:
In normal subjects, IOP was significantly smaller in the GG genotype subjects who did not have the risk allele for CDKN2B-AS1.