Investigation of the associations between primary open-angle glaucoma and rho proteins gene polymorphisms

Primary open-angle glaucoma (POAG) is a multifactorial disease that causes irreversible blindness. The hypothesis that Rho protein polymorphisms may play a role in POAG development is examined in this study. The aim of this research is to investigate the association of Rho proteins gene polymorphisms and POAG in Turkish population. A total of 179 POAG patients and 182 healthy subjects (control group) with similar age and gender were enrolled in this study. Genomic DNA was isolated from peripheral leukocyte and RhoA (rs6784820, rs974495), RhoB (rs62121967, rs11541350), RhoC (rs11102522), RhoD (rs61891303, rs2282502), and RND3 (RhoE) (rs112924194) gene polymorphisms were identified by using BioMark HD dynamic array system with real-time PCR. Genotype and allele frequencies were evaluated with chi-square or Fisher's exact tests, and haplotypes were analysed with SHEsis programme. There was a significant increase in mean intraocular pressure in glaucoma group (28.7±6.6 vs. 13.5±3.4 mmHg, P<0.0001). Genotype distributions for RhoA gene rs974495 polymorphism were found to be 53.9%, 34.8%, and 11.2% for CC, CT, and TT, respectively. When compared these distributions to the control group (CC: 52.2%, CT: 45.6%, and TT: 2.2%), significant association was detected for TT genotype (P=0.0021) with increasing the risk of glaucoma for 4.9 times. Allele frequencies, haplotype analysis, and the other polymorphisms studied showed no significant associations. Our results is the first to demonstrate that there is significant association between POAG and RhoA gene rs974495 polymorphism in Turkish population and showing that the presence of TT genotype can be a risk factor for POAG. Key Words: Haplotype analysis, Polymorphism, Primary open-angle glaucoma, RhoA, Rho proteins