Association study of multiple gene polymorphisms with the risk of adult-onset primary open-angle glaucoma in a Mexican population

Association between optic atrophy 1 polymorphisms and primary open angle glaucoma risk: Based on a meta-analysis

BACKGROUND

Emerging evidence suggested a significant association between optic atrophy 1 (OPA1) polymorphisms and primary open angle glaucoma (POAG) risk. However, the current data are inconsistent or even contradictory. Given these, we conducted a meta-analysis to examine the precise association between OPA1 polymorphisms and POAG risk.

MATERIALS AND METHODS

Online databases were retrieved, and the related studies were reviewed from inception to December 1, 2022. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to examine the statistical power of each genetic model. In addition, heterogeneity, sensitivity, cumulative analysis, and publication bias were analyzed to guarantee statistical power.

RESULT

Overall, 14 studies within 11 publications (involving 2,413 POAG patients and 1,904 controls) were included and some significant association between OPA1 rs166850 C/T (T vs. C: OR = 1.24, 95%CI = 1.06-1.45, P = 0.01, I2 = 39.0%; CT vs. CC: OR = 1.37, 95%CI = 1.05-1.79, P = 0.02, I2 = 41.6%; CT + TT vs. CC: 1.37, 95%CI = 1.06-1.77, P = 0.02, I2 = 41.6%), rs10451941T/C (TC + CC vs. TT: OR = 1.79, 95%CI = 1.41-2.28, P < 0.01, I2 = 71.9%) polymorphisms and POAG susceptibility. In addition, further significant associations were also observed in the stratified analysis, especially in normal tension glaucoma groups and Caucasian descendants.

CONCLUSION

The observed evidences suggest that OPA1 polymorphisms may be associate with POAG susceptibility significantly.

The Role of Mitophagy in Glaucomatous Neurodegeneration

This review aims to provide a better understanding of the emerging role of mitophagy in glaucomatous neurodegeneration, which is the primary cause of irreversible blindness worldwide. Increasing evidence from genetic and other experimental studies suggests that mitophagy-related genes are implicated in the pathogenesis of glaucoma in various populations. The association between polymorphisms in these genes and increased risk of glaucoma is presented. Reduction in intraocular pressure (IOP) is currently the only modifiable risk factor for glaucoma, while clinical trials highlight the inadequacy of IOP-lowering therapeutic approaches to prevent sight loss in many glaucoma patients. Mitochondrial dysfunction is thought to increase the susceptibility of retinal ganglion cells (RGCs) to other risk factors and is implicated in glaucomatous degeneration. Mitophagy holds a vital role in mitochondrial quality control processes, and the current review explores the mitophagy-related pathways which may be linked to glaucoma and their therapeutic potential.

Association of MTHFR C677T polymorphism with primary open angle glaucoma: a Meta-analysis based on 18 case-control studies

AIM

To systematically understand the genetic association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and primary open angle glaucoma (POAG).

METHODS

A comprehensive literature search in Google Scholar, PubMed, Science Citation Index, Foreign Medical Literature Retrieval Service, Chinese National Knowledge Infrastructure and Wanfang Databases was performed to collect all eligible studies up to August 2019. Study selection, data abstraction and study quality evaluation were performed by two independent investigators. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the association.

RESULTS

Eighteen case-control studies including 2156 cases and 2201 controls were identified. There was no significant difference in the terms of MTHFR C677T polymorphism and POAG in the Caucasian population (for T vs C OR=1.11, 95%CI: 0.88 to 1.39; for TT vs CC OR=1.01, 95%CI: 0.76 to 1.36; for TT+TC vs CC OR=1.15, 95%CI: 0.84 to 1.58 and for TT vs TC+CC OR=1.02, 95%CI: 0.78 to 1.33). However, a significant effect was revealed in the Asian population (for T vs C OR=1.34, 95%CI: 1.12 to 1.59; for TT+TC vs CC OR=1.41, 95%CI: 1.14 to 1.76).

CONCLUSION

Based on 18 eligible studies, we provide a correlation between MTHFR C677T polymorphism and POAG among the Asians subgroup indicating that the T allele or TT +TC genotype may play a critical role in POAG development in Asians.

Molecular Genetics of Glaucoma: Subtype and Ethnicity Considerations

Glaucoma, the world’s leading cause of irreversible blindness, is a complex disease, with differential presentation as well as ethnic and geographic disparities. The multifactorial nature of glaucoma complicates the study of genetics and genetic involvement in the disease process. This review synthesizes the current literature on glaucoma and genetics, as stratified by glaucoma subtype and ethnicity. Primary open-angle glaucoma (POAG) is the most common cause of glaucoma worldwide, with the only treatable risk factor (RF) being the reduction of intraocular pressure (IOP). Genes associated with elevated IOP or POAG risk include: ABCA1, AFAP1, ARHGEF12, ATXN2, CAV1, CDKN2B-AS1, FOXC1, GAS7, GMDS, SIX1/SIX6, TMCO1, and TXNRD2. However, there are variations in RF and genetic factors based on ethnic and geographic differences; it is clear that unified molecular pathways accounting for POAG pathogenesis remain uncertain, although inflammation and senescence likely play an important role. There are similar ethnic and geographic complexities in primary angle closure glaucoma (PACG), but several genes have been associated with this disorder, including MMP9, HGF, HSP70, MFRP, and eNOS. In exfoliation glaucoma (XFG), genes implicated include LOXL1, CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A. Despite tremendous progress, major gaps remain in resolving the genetic architecture for the various glaucoma subtypes across ancestries. Large scale carefully designed studies are required to advance understanding of genetic loci as RF in glaucoma pathophysiology and to improve diagnosis and treatment options.

Correlation between MTHFR polymorphisms and glaucoma: A meta-analysis

Background

Whether methylenetetrahydrofolate reductase (MTHFR) polymorphisms are implicated in glaucoma remains controversial. Therefore, we performed this study to better assess the relationship between MTHFR polymorphisms and the likelihood of glaucoma.

Methods

A systematic research of PubMed, Medline, and Embase was performed to retrieve relevant articles. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

Results

A total of 18 studies with 7,168 participants were analyzed. In overall analyses, a significant association with the likelihood of glaucoma was detected for the rs1801133 polymorphism in dominant (p = 0.04, OR = 0.90, 95%CI 0.81–1.00) and allele (p = 0.02, OR = 0.91, 95%CI 0.84–0.98) comparisons. Further, subgroup analyses by ethnicity revealed that both rs1801131 and rs1801133 polymorphisms were significantly associated with the likelihood of glaucoma in West Asians. However, no positive results were detected for two investigated polymorphisms in East Asians and Caucasians.

Conclusion

Our findings indicated that rs1801131 and rs1801133 polymorphisms may serve as genetic biomarkers of glaucoma in West Asians.

GSTM1-null and GSTT1-active genotypes as risk determinants of primary open angle glaucoma among smokers

AIM

To evaluate glutathione transferase theta 1 and mu 1 (GSTT1 and GSTM1) polymorphisms as determinants of primary open angle glaucoma (POAG) risk, independently or in combination with cigarette smoking, hypertension and diabetes mellitus.

METHODS

A case-control study with 102 POAG patients and 202 age and gender-matched controls was carried out. Multiplex-polymerase chain reaction method was used for the analysis of GSTM1 and GSTT1 polymorphisms. The differences between two groups were tested by the t-test or χ² test. Logistic regression analysis was used for assessing the risk for disease development.

RESULTS

The presence of GSTM1-null genotype did not contribute independently towards the risk of POAG. However, individuals with GSTT1-active genotype were at almost two-fold increased risk to develop glaucoma (P=0.044) which increased up to 4.36 when combined with GSTM1-null carriers (P=0.024). When glutathione transferase (GST) genotypes were analyzed in association with cigarette smoking, hypertension and diabetes, only carriers of GSTT1-active genotype had significantly increased risk of POAG development in comparison with GSTT1-null genotype individuals with no history of smoking, hypertension and diabetes, respectively (OR=3.52, P=0.003; OR=10.02, P<0.001; OR=4.53, P=0.002).

CONCLUSION

The results obtained indicate that both GSTM1-null and GSTT1-active genotypes are associated with increased POAG risk among smokers, suggesting potential gene-environment interaction in glaucoma development.

Glutathione S-transferase (GSTM1, GSTT1) polymorphisms and JOAG susceptibility: A case control study and meta-analysis in glaucoma

PURPOSE

Glutathione S transferase (GST) polymorphisms have been considered risk factors for the development of glaucoma. The aim of the present study was to investigate the association of glutathione S-transferase GSTT1 and GSTM1 genotypes with juvenile open-angle glaucoma (JOAG) in Indian patients.

METHODS

A case-control study was performed to investigate the associations of GSTM1 and GSTT1 in juvenile open-angle glaucoma. The genotype of GSTM1 and GSTT1 were determined in 73 juvenile open-angle glaucoma patients, and 70 controls matched by age and sex by polymerase chain reaction method. We also performed a meta-analysis of sixteen published studies on GSTM1 and GSTT1 and evaluated the association between the GSTM1 and GSTT1 polymorphisms and glaucoma (JOAG & POAG). Published literature from PubMed and other databases were retrieved. All studies evaluating the association between GSTM1 and GSTT1 polymorphisms and glaucoma (JOAG & POAG) risk were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using random- or fixed-effects model.

RESULTS

In the present study, we observed there is no association of GSTM1 (OR=0.680; 95% CI=0.323-1.433; p=0.311) or GSTT1 (OR=0.698; 95% CI=0.307-1.586; p=0.391) with JOAG. In the present meta-analysis, significantly increased glaucoma (JOAG & POAG) risk was found among subjects carrying GSTM1 null genotype (OR=1.177; 95% CI=1.028-1.348; p=0.018) but not among subjects carrying GSTT1 deletion genotype (OR=1.186; 95% CI=0.992-1.417; p=0.061).

CONCLUSIONS

The present case-control study found that GSTM1 and GSTT1 polymorphism are not associated with JOAG risk in North Indian population. The present meta-analysis suggested that there might be a significant association of GSTM1 null genotype with glaucoma (JOAG & POAG) risk. To the best of our knowledge, this is the first study in the world to investigate role of GSTM1 and GSTT1 polymorphisms with JOAG susceptibility. Given the limited sample size, the associations between GST polymorphism and glaucoma risk needs further investigation.

Association of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with primary glaucoma in Saudi population

Background

Methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate metabolism is involved in DNA synthesis, DNA repair and DNA methylation. The functional polymorphism of MTHFR gene, C677T has been shown to impact various diseases and implicated as a risk factor for the development of various neurodegenerative disorders including glaucoma.

Methods

We investigated MTHFR C677T genotypes and alleles frequencies in primary glaucoma [primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG)] patients and matched healthy controls in a case-control study. Two hundred ten primary glaucoma cases were studied for MTHFR C677T polymorphism and compared with 280 controls taken from the healthy population, employing the polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP). The MTHFR gene was amplified using specific primers. The PCR products (294 bp) was subsequently digested with HinfI (New England Biolabs) at 37 °C for 12 h, separated by electrophoresis on 2 % agarose gels, and visualized with ethidium bromide staining. The restriction digestion yielded 168 and 126 bp fragments for TT, 294, 168 and 126 bp fragments for CT and undigested PCR product 294 bp indicating CC genotype.

Results

We found the frequency of the genotypes and alleles of MTHFR C677T differ significantly between cases and controls. The frequencies of allele T and genotype CT were significantly higher while the frequencies of allele C and genotype CC were lower in primary glaucoma patients as compared to controls (p <0.05). Upon stratification of our results into POAG and PACG, significantly higher frequencies of allele T (19.44 %) and genotype CT (38.89 %) were found in POAG patients compared to controls (12.5 % and 25 % respectively). The frequencies of alleles and genotypes were almost similar in PACG and controls (p = 0.8).

Conclusion

This study indicates that the allele T and genotype CT of MTHFR C677T polymorphism are significantly associated with POAG while allele C and CC genotype may be protective for it. We conclude that the MTHFR C677T polymorphism increases the risk for POAG development in Saudi population and can be a genetic marker however, further studies are needed with multiple-ethnic populations affected with POAG to strengthen these findings.

The effect of MTHFR ala222val polymorphism on open-angle glaucoma: a meta-analysis

Glaucoma is the second leading cause of irreversible blindness worldwide, among which primary open-angle glaucoma (POAG) is the most common form of glaucoma in some populations. To date, published data on the association between MTHFR (Ala222Val) polymorphism and POAG risk are still inconclusive. In this work, we performed a meta-analysis of available case-control study in order to assess the association between MTHFR (Ala222Val) polymorphism and POAG susceptibility. In total we compiled 13 studies (1970 POAG patients and 1712 control subjects) into the meta-analysis. Overall, no obvious associations between MTHFR (Ala222Val) polymorphism and POAG susceptibility was found under all four genetic models (Val/Val versus Ala/Ala: OR = 1.05, 95% CI = 0.77-1.43; Ala/Val versus Ala/Ala: OR = 1.05, 95% CI = 0.86-1.26; Ala/Val + Val/Val versus Ala/Ala: OR = 1.08, 95% CI = 0.87-1.34; Val/Val versus Ala/Val + Ala/Ala: OR = 1.14, 95% CI = 0.67-1.92). In the stratified analysis by ethnicity, significant associations were still not observed in all genetic models. In conclusion, based on 13 eligible studies, the result provided strong evidences that MTHFR Ala222Val polymorphism is not associated with POAG.

Are glutathione S-transferase polymorphisms (GSTM1, GSTT1) associated with primary open angle glaucoma? A meta-analysis

BACKGROUND

Glutathione S-transferase (GST) variants have been considered as risk factors for the pathogenesis of primary open angle glaucoma (POAG). However, the results have been inconsistent. In this study, we performed a meta-analysis to assess the association between GSTM1 and GSTT1 null genotypes and the risk for POAG.

METHODS

Published literature from PubMed and EMBASE databases was retrieved. All studies evaluating the association between GSTM1/GSTT1 variants and POAG were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using fixed- or random-effects model.

RESULTS

14 studies (1711 POAG cases and 1537 controls) were included in the meta-analysis of GSTM1 genotypes and 10 studies (1306 POAG cases and 1114 controls) were included in the meta-analysis of GSTT1 genotypes. The overall result showed that the association between GSTM1 and GSTT1 null genotypes and risk for POAG was not statistically significant (GSTM1: OR=1.19, 95% CI=0.82-1.73, p=0.361; GSTT1: OR=1.26, 95% CI=0.77-2.06, p=0.365). The results by ethnicity showed that the association between the GSTM1 null genotype and risk for POAG is statistically significant in East Asians (OR=1.41, 95% CI=1.04-1.90, p=0.026), but not in Caucasians (OR=1.13, 95% CI=0.69-1.84, p=0.638) and Latin-American (OR=1.09, 95% CI=0.62-1.92, p=0.767). In addition, there was no significant association of GSTT1 null genotype with risk for POAG in either ethnic population.

CONCLUSIONS

The present meta-analysis suggested that there might be a significant association of GSTM1 null genotype with POAG risk in East Asians.