GENETIC POLYMORPHISMS ASSOCIATED WITH PRIMARY OPEN-ANGLE GLAUCOMA: A SYSTEMATIC REVIEW

Abstract

Background: Primary Open-Angle Glaucoma (POAG) is the predominant type of glaucoma and causes irreversible blindness that is a major cause of blindness in the world. There is growing evidence that genetics is a crucial issue in the evolution and course of POAG. Consequently, it is necessary to synthesize the existing evidence to gain a better insight into the genetic architecture of POAG susceptibility.

Methodology: A systematic review was performed to find the studies that assessed genetic polymorphisms that were related to POAG. Eligible studies that examined genetic variants in patients with POAG were searched in electronic databases. These studies were case-control studies, mutation screening studies, and genome-wide association studies, which are all observational genetic association studies, whereas reviews and meta-analyses were excluded. Information obtained in the reviewed studies was in the form of study design, population of the study, sample size, genetic analysis procedures, genes under investigation, and results.

Findings: The review was comprised of 17 studies that were carried out in various regions. The majority of the studies involved case-control designs and involved the use of molecular methods including PCR-based genotyping, DNA sequencing or genome-wide SNP arrays to test genetic variants. The genes that were investigated included the established glaucoma-related genes, such as MYOC, OPTN, and WDR36, and the loci found in genome-wide research, such as CAV1/CAV2, CDKN2B-AS1, SIX1/SIX6, PLXDC2, and GAS7. A number of variants exhibited great relationships with POAG susceptibility specifically polymorphisms of MYOC, CDKN2B-AS1, CAV1/CAV2 and CAT genes.

Conclusion: The results of this systematic review show that POAG is affected by various genetic polymorphisms that influence a variety of biological pathways such as the structure of the optic nerve, vascular controls, and oxidative stress. Although some of the genes like MYOC and CDKN2B-AS1 seem to have important contributions in the susceptibility of the disease, the general genetic structure of POAG is not homogenous among populations.