Role of the vitamin K epoxide reductase complex subunit 1 (VKORC1) -1639G>A gene polymorphism in patients with retinal vein occlusion

PON1, APOE and SDF-1 Gene Polymorphisms and Risk of Retinal Vein Occlusion: A Case-Control Study

Numerous studies have tried to evaluate the potential role of thrombophilia-related genes in retinal vein occlusion (RVO); however, there is limited research on genes related to different pathophysiological mechanisms involved in RVO. In view of the strong contribution of oxidative stress and inflammation to the pathogenesis of RVO, the purpose of the present study was to investigate the association of inflammation- and oxidative-stress-related polymorphisms from three different genes [apolipoprotein E (APOE), paraoxonase 1 (PON1) and stromal cell-derived factor 1 (SDF-1)] and the risk of RVO in a Greek population. Participants in this case-control study were 50 RVO patients (RVO group) and 50 healthy volunteers (control group). Blood samples were collected on EDTA tubes and genomic DNA was extracted. Genotyping of rs854560 (L55M) and rs662 (Q192R) for the PON1 gene, rs429358 and rs7412 for the APOE gene and rs1801157 [SDF1-3'G(801)A] for SDF-1 gene was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Multiple genetic models (codominant, dominant, recessive, overdominant and log-additive) and haplotype analyses were performed using the SNPStats web tool to assess the correlation between the genetic polymorphisms and the risk of RVO. Binary logistic regression analysis was used for the association analysis between APOE gene variants and RVO. Given the multifactorial nature of the disease, our statistical analysis was adjusted for the most important systemic risk factors (age, hypertension and diabetes mellitus). The dominant genetic model for the PON1 Q192R single nucleotide polymorphism (SNP) of the association analysis revealed that there was a statistically significant difference between the RVO group and the control group. Specifically, after adjusting for age and hypertension, the PON1 192 R allele (QR + RR) was found to be associated with a statistically significantly higher risk of RVO compared to the QQ genotype (OR = 2.51; 95% CI = 1.02-6.14, p = 0.04). The statistically significant results were maintained after including diabetes in the multivariate model in addition to age and hypertension (OR = 2.83; 95% CI = 1.01-7.97, p = 0.042). No statistically significant association was revealed between the other studied polymorphisms and the risk of RVO. Haplotype analysis for PON1 SNPs, L55M and Q192R, revealed no statistically significant correlation. In conclusion, PON1 192 R allele carriers (QR + RR) were associated with a statistically significantly increased risk of RVO compared to the QQ homozygotes. These findings suggest that the R allele of the PON1 Q192R is likely to play a role as a risk factor for retinal vein occlusion.

Diabetes mellitus as a risk factor for retinal vein occlusion: A meta-analysis

Retinal vein occlusion (RVO) is the second most common etiology for vision loss. There is contrasting evidence on the association between diabetes mellitus (DM) and the risk of RVO. We performed a meta-analysis of published articles before October 31, 2019, to estimate a pooled odds ratio for the association between DM and RVO, including central and branch RVO by a fixed or random effects model. We identified 37 publications from 38 studies (1 publication was from 2 studies), published between 1985 and 2019. In total, 148,654 cases and 23,768,820 controls were included in this meta-analysis. The results of pooled analysis for all 37 publications (or 38 studies) showed a significant association between DM and the risk of RVO (OR = 1.68, 95% CI: 1.43-1.99). Subgroup analysis indicated that DM was significantly associated with CRVO (OR = 1.98, 95% CI: 1.29-3.03, I = 67.9%), but not significantly associated with BRVO (OR = 1.22, 95% CI: 0.95-1.56, I = 64.1%). In conclusion, the result of present meta-analysis suggested that DM is a risk factor for RVO. More well-designed studies on the relationship between RVO and DM should be undertaken in the future.

Genetic polymorphisms associated with the prevalence of retinal vein occlusion in a Greek population

PURPOSE

To investigate possible associations of single-nucleotide polymorphisms (SNPs) from five genes with branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

METHODS

A total of 69 patients with retinal vein occlusion-RVO (24 with BRVO and 45 with CRVO), and 82 controls, were enrolled in this study. All subjects were screened for hypertension, diabetes mellitus, hyperlipidemia, glaucoma, anticoagulant medication, smoking status and history of stroke. The genotyping of AGTR1-A1166C, adiponectin + 276 G/T, MMP2-1306C/T, Gpla/lla-C807T/G873A and VKORC1-G1639A polymorphisms was performed using restriction fragment length polymorphism or allele-specific polymerase chain reaction.

RESULTS

The percentage of the AGTR1-A1166C C allele carriers and Gpla/lla-C807T/G873A T/A carriers was significantly higher in the CRVO patients than in the controls (P = 0.00001 and P = 0.0004, respectively). At the multiple logistic regression analysis, the AGTR1-A1166C C allele carrier status and the Gpla/lla-C807T/G873A T/A allele carrier status were found to be associated with an increased risk of CRVO. Moreover, adiponectin + 276 G/T T allele carriers had a significantly increased risk of RVO in subjects ≥ 75 years old. There was no significant difference between the BRVO patients and controls concerning the genotype or the allele frequency distributions of these SNPs. The genotype distributions or allelic frequencies of the other evaluated polymorphisms did not significantly differ between the patients with RVO and the control subjects.

CONCLUSIONS

AGTR1 A1166C and Gpla/lla C807T/G873A polymorphisms are likely to be risk factors for CRVO. Adiponectin + 276 G/T SNP is likely to predispose to RVO in older subjects.

Developments in Ocular Genetics: 2013 Annual Review

PURPOSE

To highlight major advancements in ocular genetics from the year 2013.

DESIGN

Literature review.

METHODS

A literature search was conducted on PubMed to identify articles pertaining to genetic influences on human eye diseases. This review focuses on manuscripts published in print or online in the English language between January 1, 2013 and December 31, 2013. A total of 120 papers from 2013 were included in this review.

RESULTS

Significant progress has been made in our understanding of the genetic basis of a broad group of ocular disorders, including glaucoma, age-related macular degeneration, cataract, diabetic retinopathy, keratoconus, Fuchs' endothelial dystrophy, and refractive error.

CONCLUSIONS

The latest next-generation sequencing technologies have become extremely effective tools for identifying gene mutations associated with ocular disease. These technological advancements have also paved the way for utilization of genetic information in clinical practice, including disease diagnosis, prediction of treatment response and molecular interventions guided by gene-based knowledge.