APOE ε2-Carriers Are Associated with an Increased Risk of Primary Angle-Closure Glaucoma in Patients of Saudi Origin

This study investigated the association between apolipoprotein E (APOE) gene polymorphisms (rs429358 and rs7412) and primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG) in a Saudi cohort. Genotyping of 437 DNA samples (251 controls, 92 PACG, 94 PXG) was conducted using PCR-based Sanger sequencing. The results showed no significant differences in the allele and genotype frequencies of rs429358 and rs7412 between the PACG/PXG cases and controls. Haplotype analysis revealed ε3 as predominant, followed by ε4 and ε2 alleles, with no significant variance in PACG/PXG. However, APOE genotype analysis indicated a significant association between ε2-carriers and PACG (odds ratio = 4.82, 95% CI 1.52-15.26, p = 0.007), whereas no notable association was observed with PXG. Logistic regression confirmed ε2-carriers as a significant predictor for PACG (p = 0.008), while age emerged as significant for PXG (p < 0.001). These findings suggest a potential role of ε2-carriers in PACG risk within the Saudi cohort. Further validation and larger-scale investigations are essential to elucidate the precise role of APOE in PACG pathogenesis and progression.

Common Variants rs429358 and rs7412 in APOE Gene Are Not Associated with POAG in a Saudi Cohort

Adult-onset glaucoma, an age-related neurodegenerative disease, is very prevalent among the elderly Arabs of Saudi origin. This study investigated the association between apolipoprotein E (APOE) gene variants (rs429358 and rs7412) and primary open-angle glaucoma (POAG) in Arabs of Saudi origin. A case-control genetic association study involving 179 POAG patients and 251 controls utilized Sanger sequencing to genotype APOE gene variants. The allele frequencies and genotype distributions for rs429358 and rs7412 did not show significant associations with POAG. The haplotype analysis revealed apoε3 (87.6% and 87.4%) as the most prevalent, followed by ε4 (2.8% and 3.6%) and ε2 (9.6% and 8.9%) in the controls and POAG patients, respectively. Although the ε2/ε3 genotype and ε2-carriers displayed a more than two-fold increased risk, statistical significance was not reached. Notably, these polymorphisms did not affect clinical markers, such as intraocular pressure and cup/disc ratio. The logistic regression analysis demonstrated no significant influence of age, sex, rs429358, or rs7412 polymorphisms on POAG. In conclusion, within the Saudi cohort, APOE variants (rs429358 and rs7412) do not appear to be associated with POAG and are not substantial risk factors for its development. However, additional population-based studies are required to validate these findings.

Association between Polymorphism rs61876744 in PNPLA2 Gene and Keratoconus in a Saudi Cohort

The genetic etiology of Keratoconus (KC) in Middle Eastern Arabs of Saudi origin is still unclear. A recent genome-wide study identified two significant loci in the region of PNPLA2 (rs61876744) and CSNK1E (rs138380) for KC that may be associated with KC in the Saudi population. In addition, polymorphisms in the apolipoprotein E (APOE) gene, namely, rs429358 and rs7412, responsible for APOE allelic variants ε2, ε3, and ε4, may influence KC via oxidative stress mechanism(s). Thus, we investigated the possible association of polymorphisms rs61876744, rs138380, rs429358, rs7412, and APOE genotypes in KC patients of the Saudi population. This study included 98 KC cases and 167 controls. Polymorphisms rs6187644 and rs138380 were genotyped using TaqMan assays, and rs429358 and rs7412 were genotyped via Sanger sequencing. Although the allele frequency of rs61876744(T) in PNPLA2 was a protective effect against KC (odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.44-0.93), the p-value (p = 0.020) was not significant for multiple testing correction (p = 0.05/4 = 0.015). However, rs6187644 genotype showed a modestly significant protective effect in the dominant model (OR = 0.53, 95% CI = 0.32-0.88, p = 0.013). Polymorphisms rs138380, rs429358, and rs7412 showed no significant allelic or genotype association with KC. However, the ε2-carriers (ε2/ε2 and ε2/ε3 genotypes) exhibited a greater than 5-fold increased risk of KC, albeit non-significantly (p = 0.055). Regression analysis showed no significant effect of age, gender, and the four polymorphisms on KC. Our results suggest that polymorphism rs6187644 in PNPLA2 might be associated with KC in the Middle Eastern Arabs of Saudi origin but warrant a large-scale association analysis at this locus.

The 3' UTR polymorphisms rs3742330 in DICER1 and rs10719 in DROSHA genes are not associated with primary open-angle and angle-closure glaucoma: As case-control study

AIM

In a retrospective and exploratory case-control study, we examined the genetic association of two common polymorphisms in the 3' untranslated region (UTR) of DICER1 (rs3742330) and DROSHA (rs10719) genes in primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and its related clinical phenotypes in a Saudi cohort.

METHODS

DNA genotyping was performed using TaqMan real-time PCR assays in 500 participants, including 152 POAG, 102 PACG, and 246 non-glaucomatous controls. Statistical analyses were performed to examine the association(s).

RESULTS

Allele and genotype frequency of rs3742330 and rs10719 did not vary significantly in POAG and PACG compared to controls. No significant deviation was observed from Hardy-Weinberg Equilibrium (p > 0.05). Gender stratification revealed no significant allelic/genotype association with glaucoma types. Also, these polymorphisms showed no significant genotype effect on clinical markers such as intraocular pressure, cup/disc ratio, and the number of antiglaucoma medications. Logistic regression showed no effect of age, sex, rs3742330, and rs10719 genotypes on the risk of disease outcome. We also examined a combined allelic effect of rs3742330 (A>G) and rs10719 (A>G). However, none of the allelic combinations significantly affected POAG and PACG.

CONCLUSIONS

The 3' UTR polymorphisms rs3742330 and rs10719 of DICER1 and DROSHA genes are not associated with POAG and PACG or its related glaucoma indices in this Middle-Eastern cohort of Saudi Arab ethnicity. However, there is a need to validate the results on a broader population and other ethnicities.

Evaluation of ABCA1 and FNDC3B Gene Polymorphisms Associated With Pseudoexfoliation Glaucoma and Primary Angle-Closure Glaucoma in a Saudi Cohort

Objective: It is plausible that common disease mechanisms exist in glaucoma pathophysiology. Accordingly, we investigated the genetic association of two previously reported primary open-angle glaucoma (POAG)-related gene polymorphisms, rs2472493 (A > G) in ABCA1 and rs7636836 (C > T) in FNDC3B, in primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG).

Methods: TaqMan genotyping was performed in a total of 442 subjects consisting of 246 healthy controls, 102 PACG patients, and 94 PXG patients. Statistical evaluations were performed to detect allelic and genotype association of the variants with the disease and clinical variables such as intraocular pressure (IOP) and cup/disc ratio.

Results: Overall, there was no allelic or genotype association of these variants in PACG and PXG. However, rs7636836[T] allele significantly increased the risk of PXG among men (p = 0.029, odds ratio [OR] = 2.69, 95% confidence interval = 1.11–6.51). Similarly, rs2472493 and rs7636836 genotypes also showed significant association with PXG among men in over-dominant model (p = 0.031, OR = 1.98, 95% CI = 1.06–3.71) and co-dominant model (p = 0.029, OR = 2.69, 95% CI = 1.11–6.51), respectively. However, none survived Bonferroni’s correction. Besides, the synergic presence of rs2472493[G] and rs7636836[T] alleles (G-T) was found to significantly increase the risk of PACG (p = 0.026, OR = 2.85, 95% CI = 1.09–7.46). No significant genotype influence was observed on IOP and cup/disc ratio.

Conclusion: Our results suggest that the polymorphisms rs2472493 in ABCA1 and rs7636836 in FNDC3B genes may be associated with PXG among men, and a G-T allelic combination may confer an increased risk of PACG in the middle-eastern Saudi cohort. Further research in a larger population-based sample is needed to validate these findings.

Acute hydrops as an atypical presentation of primary congenital glaucoma

Primary congenital glaucoma (PCG) is a disease of childhood characterized by elevated intraocular pressure (IOP) that causes stretching of the eye's outer coats, namely sclera and cornea. This results in the elongation of the eyeball and expansion of the horizontal corneal diameter giving the appearance of a buphthalmos eye. Aggressive disease with high IOP readings causes excessive mechanical stretching that may be poorly tolerated by the corneal Descemet's membrane, leading to large breaks in it with subsequent corneal edema due to sudden influx of the aqueous humor into the exposed stroma, resulting in acute corneal hydrops. While acute hydrops is a potential sequel of PCG, it is considered one of its rare presentations. We present two cases who presented to our hospital with acute hydrops secondary to PCG. Both patients were managed surgically where the first patient underwent combined trabeculotomy-trabeculectomy with mitomycin C, while the second patient underwent deep sclerectomy with mitomycin C. The surgical procedures effectively controlled the IOP and aided in clearing corneal edema in both patients. Early diagnosis and timely surgical intervention are of paramount importance to improve visual outcomes, enhance ocular maturation, and prevent potential irreversible vision loss, especially in this young-age group of patients that are prone to amblyopia.

Bilateral Multiple Ciliary Body Cysts with Angle-Closure Glaucoma in an 18-Year-Old Patient

We present the rare case of an 18-year-old medically free male who had a history of decrease in vision in the left eye (LE) in the last 4 years. On examination, best-corrected visual acuity was 20/20 in the right eye (RE) and counting fingers 3 feet in the LE. Intraocular pressure was 34 and 40 mmHg in RE and LE, respectively. Fundus examination showed cupping of 0.7 on the RE and 0.9 on the LE. Gonioscopy revealed bilateral angle closure with a double-hump sign. Ultrasound biomicroscopy showed multiple ciliary body cysts replacing ciliary body sulcus space bilaterally.

Polymorphism rs3742330 in microRNA Biogenesis Gene DICER1 Is Associated with Pseudoexfoliation Glaucoma in Saudi Cohort

We investigated the association between DICER1 (rs3742330) and DROSHA (rs10719) polymorphisms and pseudoexfoliation glaucoma (PXG) and related clinical phenotypes in a Saudi cohort. In a retrospective case-control study, TaqMan real-time, PCR-based genotyping was performed in 340 participants with 246 controls and 94 PXG cases. The minor (G) allele frequency of rs3742330 in PXG (0.03) was significantly different from that in the controls (0.08) and protective against PXG (odds ratio (OR) = 0.38, 95% confidence interval (CI) = 0.16–0.92), p = 0.017). Similarly, the rs3742330 genotypes showed a significant protective association with PXG in dominant (p = 0.019, OR = 0.38, 95% CI = 0.15–0.92), over-dominant (p = 0.024, OR = 0.39, 95% CI = 0.16–0.95), and log-additive models (p = 0.017, OR = 0.38, 95% CI = 0.16–0.92). However, none remained significant after an adjustment for age, sex, and multiple testing. Rs10719 in DROSHA did not show any significant allelic or genotype association with PXG. However, a protective effect of the GA haplotype in DICER1 and DROSHA and PXG (p = 0.034) was observed. Both polymorphisms showed no significant effect on intraocular pressure and the cup–disk ratio. In conclusion, we report a significant genetic association between variant rs3742330 in DICER1, a gene involved in miRNA biogenesis, and PXG. Further investigation in a larger group of patients of different ethnicities and functional studies are warranted to replicate and validate its potential role in PXG.

Association analysis of variants rs35934224 in TXNRD2 and rs6478746 in LMX1B in primary angle-closure and pseudoexfoliation glaucoma

OBJECTIVE

Previous genome-wide studies have demonstrated significant pathogenic association between variants rs35934224 within TXNRD2 and rs6478746 near LMX1B in primary open-angle glaucoma. We investigated the association between these variants in primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG) patients of Saudi origin.

METHODS

In a case-control study, DNA samples from 249 controls (135 men and 114 women), 100 PACG cases (44 men and 56 women), and 95 PXG cases (61 men and 34 women) were genotyped by TaqMan^® based real-time PCR. Statistical tests were performed to evaluate genetic association with glaucoma types and related clinical indices.

RESULTS

The allele frequencies of rs35934224 and rs6478746 did not show significant variation in PACG and PXG than controls, except that the rs35934224[T] allele was found to be significantly low among PXG women (0.10) as compared to controls (0.21) (odds ratio = 0.38, 95% confidence interval = 0.16-0.94, p = 0.024). Rs35934224 genotypes showed a nominal-to-borderline protective association with PACG and PXG among women in different genetic models. However, except for the over-dominant model in PACG (p = 0.0095), none of the effects survived Bonferroni's correction (p < 0.01). Rs6478746 showed no significant genotype or allelic association with PACG and PXG. Regression analysis showed no influence on disease outcome, and neither showed any correlation with intraocular pressure and cup/disk ratio in both PACG and PXG.

CONCLUSIONS

Variants rs35934224 in TXNRD2 and rs6478746 near LMX1B are not associated with PACG and PXG in the Saudi cohort, but rs35934224 may confer modest protection among women. Further population-based studies are needed to validate these results.

Lack of Association Between Polymorphisms in TXNRD2 and LMX1B and Primary Open-Angle Glaucoma in a Saudi Cohort

Objective: Recent studies have demonstrated an association of single nucleotide polymorphisms (SNPs) rs35934224 in TXNRD2 and rs6478746 near LMX1B genes in primary open-angle glaucoma (POAG) among Europeans. We performed a retrospective, case-control study to investigate the association between the rs35934224 (TXNRD2) and rs6478746 (LMX1B) and POAG in a middle-eastern population from Saudi Arabia. Methods: DNA from 399 participants consisting of 150 POAG cases (83 males and 67 females) and 249 controls (135 males and 114 females) were genotyped using TaqMan® real-time PCR. Statistical tests were performed to evaluate genetic association with POAG and related clinical indices. Results: The minor allele frequency (MAF) of rs35934224[T] was 0.19 and 0.20 in POAG and controls, respectively. The difference was non-significant (odds ratio [OR] = 1.08, 95% confidence interval [CI] = 0.75-1.55, p = 0.663). Likewise, rs6478746[G] MAF was 0.12 in both cases and controls with no statistical significance (OR = 1.02, 95% CI = 0.67-1.56, p = 0.910). Genotype analysis showed no association with POAG for both the SNPs in combined and gender-stratified groups. Regression analysis showed no significant effect of risk factors such as age, sex, rs35934224, and rs6478746 genotypes on POAG outcome. Furthermore, both the SNPs showed no significant genotype effect on clinical indices such as intraocular pressure (IOP) and cup/disc ratio in POAG patients. Conclusions: Rs35934224 in TXNRD2 and rs6478746 near LMX1B genes are not associated with POAG or related clinical indices such as IOP and cup/disc ratio in a Saudi cohort. Since the study is limited by sample size further investigations are needed to confirm these results in a larger cohort.

Association of rs12997 variant in the ACVR1 gene: a member of bone morphogenic protein signaling pathway with primary open-angle glaucoma in a Saudi cohort

We investigated the association between variants rs12997 in activin A receptor type I (ACVR1) and rs1043784 in BMP6 located in the 3' untranslated region, and primary open-angle glaucoma (POAG). The retrospective case-control study used TaqMan real-time PCR assay to genotype 400 subjects, including 150 patients with POAG and 250 controls. The minor 'G' allele of rs12997 in ACVR1 showed significant association with POAG (p=0.027, OR=1.39, 95% CI=1.03 to 1.87). Likewise, rs12997 genotypes showed moderate association with POAG in recessive (p=0.048, OR=1.80, 95% CI=1.01 to 3.20) and log-additive models (p=0.030, OR=1.39, 95% CI=1.03 to 1.87), but did not survive Bonferroni correction. Rs1043784 in BMP6 showed no associations. Furthermore, rs12997 G/G genotype significantly (p=0.033) increased the risk of POAG (twofolds) independent of age, sex and rs1043784 genotypes in regression analysis. However, clinical variables such as intraocular pressure and cup/disc ratio showed no association with both the polymorphisms. To conclude, the study shows a modest association between rs12997 in the ACVR1 gene, a member of the bone morphogenic protein signaling pathway and POAG. However, the results need further replication in large population-based cohorts and different ethnicities to validate its role as an important genetic biomarker.

Association analysis of polymorphisms rs12997 in ACVR1 and rs1043784 in BMP6 genes involved in bone morphogenic protein signaling pathway in primary angle-closure and pseudoexfoliation glaucoma patients of Saudi origin

Background

Glaucoma is a polygenic neurodegenerative disease and the second most common cause of blindness in Saudi Arabia. To test the hypothesis that genetic variants in the genes involved in the bone morphogenic protein (BMP) signaling pathway may be associated with glaucoma, we investigated the association between 3′ untranslated region variants, rs12997 in ACVR1 and rs1043784 in BMP6, and primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG).

Methods

In a case-control study, TaqMan® real-time PCR-based genotyping was done in 444 subjects consisting of 250 controls, 101 PACG and 95 PXG cases, and tested for genetic association with glaucoma-types and other clinical phenotypes.

Results

Rs12997[G] allele in ACVR1 exhibited significant 2-fold increased risk of PACG (p = 0.005) in women but not in men. Similarly, genotype analysis also showed that subjects carrying rs12997[G/G] genotype were at > 2-fold risk of PACG that remained significant after adjustment for age, sex, and Bonferroni correction in the recessive model. Furthermore, this effect was also significant in women only. In PXG, the rs12997[G/G] genotype showed a significant trend towards increased risk of the disease (OR = 2.04, 95% CI = 0.99–4.18, p = 0.049) but did not survive the Bonferroni correction. Regression analysis showed that rs12997[G/G] genotype was a significant predictor of PACG independent of age, sex, and rs1043784 genotypes. Likewise, age and rs12997[G/G] genotype showed significant effect on PXG outcome. The rs12997[A/G] genotype showed significant association with cup/disc ratio as compared to wild-type (p = 0.005) in PXG. Genotype and allele frequencies of rs1043784 in BMP6 did not show any significant association either with PACG or PXG.

Conclusions

Our results suggest that the polymorphism rs12997 in the ACVR1 gene involved in the BMP signaling pathway is significantly associated with PACG and PXG in a Saudi cohort. This is the first study to associate this variant/gene with PACG and PXG. However, further studies would be needed to replicate these findings in a large population-based cohort.

Association of endothelial nitric oxide synthase (NOS3) gene polymorphisms with primary open-angle glaucoma in a Saudi cohort

Aim

To investigate the association of endothelial nitric oxide synthase (NOS3) gene polymorphisms in patients with primary open-angle glaucoma (POAG) of Saudi origin.

Methods

This case-control study included 173 patients with POAG (94 men and 79 women) and 171 controls (98 men and 73 women). Genotyping of rs2070744 (T-786C) and rs1799983 (G894T) variants of the NOS3 gene was performed using TaqMan^® assay.

Results

Rs1799983 genotypes showed a significant association with POAG but did not survive Bonferroni correction (p_correction = 0.01). The minor ‘T’ allele was significantly associated with the risk of POAG among men (p = 0.025, odds ratio (OR) = 1.77, 95% confidence interval (CI) = 1.07–2.94). Likewise, the genotypes were significantly associated with POAG among men in dominant (p = 0.030, OR = 1.92, 95% CI = 1.06–3.48) and log-additive models (p = 0.022, OR = 1.82, 95% CI = 1.08–3.07), and after adjustment for age and smoking. Genotype and allele frequencies of rs2070744 were not significantly different between POAG cases and controls, and after sex stratification. CG haplotype was significantly protective (p = 0.011, OR = 0.52, 95% CI = 0.32–0.87) and CT haplotype conferred significantly increased risk of POAG (p = 0.016, OR = 2.60, 95% CI = 1.16–5.82) among men. Rs1799983 showed trend (p = 0.054) towards risk of POAG independent of age, gender, smoking, and rs2070744 polymorphism in logistic regression analysis. Both the polymorphisms showed no association with POAG phenotypes such as intraocular pressure and cup/disc ratio.

Conclusion

Our results suggest that the polymorphism rs1799983 and the haplotypes of rs20707440 and rs1799983 in the NOS3 gene may significantly modulate the risk of POAG in Saudi’s, particularly among men. Further larger studies are needed to confirm these findings.

Polymorphisms rs693421 and rs2499601 at locus 1q43 and their haplotypes are not associated with primary open-angle glaucoma: a case-control study

Objective

The genetic spectrum of primary open-angle glaucoma (POAG) in middle-eastern Saudi’s is still elusive. To this end, we investigated an association between rs693421, rs2499601 and their haplotypes at chromosome 1q43 locus with POAG and its related clinical phenotypes. Genotyping was performed with TaqMan^® assays. Haplotypes and their interaction analysis were carried out by SHEsis and SNPStats online tools.

Results

The minor “T” allele frequency of rs693421 was 0.48 in controls and 0.52 in cases (odds ratio (OR) = 1.15, 95% confidence interval (CI) 0.85–1.54, p = 0.368). Similarly, for rs2499601, the minor “C” allele frequency was 0.49 in controls as compared to 0.53 in cases (OR = 1.19, 95% CI 0.89–1.60, p = 0.236). Besides, genotype distribution for both these polymorphisms was also not significant in additive, dominant and recessive models. rs693421 and rs2499601, showed significant linkage disequilibrium (D’ statistics = 0.69, p < 0.001) but haplotype association was non-significant (p = 0.698). The significance did not vary after adjustment to age and sex. No significant genotype association was observed with intraocular pressure, cup/disc ratio and number of anti-glaucoma medication in POAG group. Furthermore, age, sex and genotypes did not contribute any significant risk of POAG in regression analysis. We report no association between rs693421, rs2499601 and their haplotypes with POAG and related phenotypes.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4491-x) contains supplementary material, which is available to authorized users.

Local Cytokine Expression Profiling in Patients with Specific Autoimmune Uveitic Entities

Purpose: To evaluate expression of cytokines GM-CSF, IL-11, IL-12p40, IL-12p70, IL-27p28, IL-35, APRIL, BAFF, TWEAK, and LIGHT in uveitis.Methods: Aqueous humor samples from patients with active uveitis associated with Behçet's disease (BD), sarcoidosis, HLA-B27-related inflammation, and Vogt-Koyanagi-Harada (VKH) disease and control patients were assayed with a multiplex assay.Results: Comparing all patients to controls, GM-CSF, IL-11, IL-12p40, APRIL, and BAFF were significantly increased, whereas LIGHT was significantly decreased. IL-11 and BAFF were the most strongly upregulated, being elevated 19.7-fold and 14.1-fold, respectively, compared with controls. IL-11 was significantly highest in HLA-B27 uveitis. GM-CSF, IL-11, and IL-12p40 were significantly higher in nongranulomatous uveitis (BD and HLA-B27) than in granulomatous uveitis (sarcoidosis and VKH), whereas APRIL and TWEAK were significantly higher in granulomatous uveitis.Conclusions: IL-11-driven immune responses might be more potent in nongranulomatous uveitis, particularly in HLA-B27 uveitis. BAFF and APRIL might contribute to B cell-driven autoimmune response in uveitis.

Differential CXC and CX3C Chemokine Expression Profiles in Aqueous Humor of Patients With Specific Endogenous Uveitic Entities

Purpose

To determine the levels of the neutrophil chemoattractants CXCL1, CXCL2, CXCL5, CXCL6, and CXCL8, the T helper 1 chemoattractants CXCL9, CXCL10 and CXCL11, the lymphoid chemokines CXCL12 and CXCL13 and the soluble form of the transmembrane chemokines CXCL16 and CX3CL1, in aqueous humor samples from patients with specific uveitic entities.

Methods

Aqueous humor samples from patients with active uveitis associated with Behçet's disease (n = 13), sarcoidosis (n = 8), HLA-B27-related inflammation (n = 12), Vogt-Koyanagi-Harada (VKH) disease (n = 12), and healthy controls (n = 9) were assayed with the use of a multiplex assay.

Results

All chemoattractant levels were significantly higher in all patients than in the controls. The levels of all neutrophil chemoattractants and CXCL10, CXCL16, and CX3CL1 were significantly higher in nongranulomatous uveitis (Behçet's disease and HLA-B27-associated uveitis) than in granulomatous uveitis (sarcoidosis and VKH disease), whereas the levels of the B cell chemoattractant CXCL13 were significantly higher in granulomatous uveitis than in nongranulomatous uveitis. CXCL13 levels were highest in the patients with VKH disease. CXCL9, CXCL11, and CXCL12 levels did not differ significantly.

Conclusions

Inflammation in nongranulomatous uveitis appears to be driven by neutrophils and T helper 1 lymphocytes, whereas B lymphocytes may contribute to the inflammatory process in granulomatous uveitis, particularly in VKH disease.

The CC chemokines CCL8, CCL13 and CCL20 are local inflammatory biomarkers of HLA-B27-associated uveitis

PURPOSE

To determine the concentrations of the CC chemokines CCL2, CCL7, CCL8, CCL11, CCL13, CCL20, CCL24 and CCL26 in aqueous humour (AH) samples from patients with specific uveitic entities.

METHODS

Aqueous humour samples from patients with active uveitis associated with Behçet's disease (BD) (n = 13), sarcoidosis (n = 8), HLA-B27-related inflammation (n = 12), Vogt-Koyanagi-Harada (VKH) disease (n = 12) and control patients (n = 9) were assayed with the use of a multiplex assay.

RESULTS

When considering all uveitis patients as one group, all chemokine levels except CCL2 were significantly increased compared to controls. CCL8, CCL13 and CCL20 were the most strongly upregulated, 48-fold, 118-fold and 173-fold, respectively, above control AH levels. CCL8 and CCL13 levels were significantly higher in HLA-B27-associated uveitis than in sarcoidosis and VKH disease. CCL20 levels were significantly higher in HLA-B27-associated uveitis than in BD, sarcoidosis and VKH disease. In addition, CCL20 levels were significantly higher in BD than in VKH disease. In HLA-B27-associated uveitis, CCL8, CCL13 and CCL20 were upregulated 111-fold, 255-fold and 465-fold, respectively, compared with controls. CCL8, CCL13 and CCL20 levels were significantly higher in nongranulomatous uveitis (BD and HLA-B27-associated uveitis) than in granulomatous uveitis (sarcoidosis and VKH disease).

CONCLUSION

Immune responses mediated by CCL8, CCL13 and CCL20 appear to be more potent in nongranulomatous uveitis, particularly in HLA-B27-associated uveitis.

Plexin domain containing 2 (PLXDC2) gene polymorphism rs7081455 may not influence POAG risk in a Saudi cohort

Objective

Plexin domain containing 2 (PLXDC2), a cell surface transmembrane protein receptor for pigment epithelium derived factor, is expressed in many tissues including the eye. Polymorphism rs7081455 flanking PLXDC2 has been associated with primary open angle glaucoma (POAG) and its clinical phenotypes and may have a role in POAG. Rs7081455 was genotyped in POAG cases (n = 188) and non-glaucomatous controls (n = 164) of Saudi origin using Taq-Man^® to determine any association of this variant with POAG and its endophenotypes.

Results

The risk variant, ‘G’ allele, frequency was 0.56 and 0.52 in controls and POAG cases, respectively (p = 0.197) with was no significant deviation from Hardy–Weinberg equilibrium. Genotype analysis between cases and controls revealed no significant distribution under additive (p = 0.482), dominant (p = 0.590) and recessive models (p = 0.228). In addition, glaucoma specific phenotypic traits such as intraocular pressure (IOP) and cup/disc ratio; and number of anti-glaucoma medications, used to assess severity of the disease, were also statistically non-significant. Furthermore, regression analysis showed no significant effect of age, sex and genotype on disease outcome. Rs7081455 was not associated with POAG or its clinical phenotypes such as IOP and cup/disc ratio and hence may not be a significant risk factor for POAG patients of Saudi origin.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3848-x) contains supplementary material, which is available to authorized users.

Analysis of CYP1B1 sequence alterations in patients with primary open-angle glaucoma of Saudi origin

Cytochrome P450 Family 1 Subfamily B Member 1 (CYP1B1; OMIM# 601771) gene encodes one of the cytochrome P450 family of enzymes. CYP1B1 mutations have been associated primarily with primary congenital glaucoma (PCG). Similar studies were reported in juvenile open-angle glaucoma, Rieger’s and Peters anomalies. Reports of likely pathogenic sequence alterations in families affected with adult-onset primary open-angle glaucoma (POAG) triggered this investigation. We screened unrelated POAG cases and healthy controls for mutations in CYP1B1 using automated Sanger sequencing to identify five known polymorphisms and one CYP1B1 mutation (p.G61E) in a heterozygous status. The p.G61E mutation is known to cause PCG in a homozygous or compound heterozygous form, and thus, its presence here in a heterozygous form indicates carrier status. These findings suggest that CYP1B1 may have no major role in the pathogenesis of POAG, at least, in the Saudi population. However, further investigations are needed to validate these findings in a larger cohort.

Association of increased levels of plasma tumor necrosis factor alpha with primary open-angle glaucoma

Purpose

Retinal ganglion cell (RGC) death is a key feature of glaucoma. Elevated levels of tumor necrosis factor alpha (TNF-α), a pro-inflammatory cytokine, can induce RGC apoptosis and play a critical role in glaucomatous neurodegeneration. Based on the possible role of inflammation and oxidative stress in the pathogenesis of primary open-angle glaucoma (POAG), we investigated the association between plasma levels of TNF-α and POAG or its clinical indices in comparison to non-glaucomatous controls.

Patients and methods

In a case-control retrospective cohort of 51 POAG cases and 88 controls, plasma TNF-α levels were measured using an enzyme-linked immunosorbent assay (ELISA). The assay was performed in duplicates on an automated ELISA analyzer.

Results

Mean TNF-α level was significantly elevated in POAG cases (1.88 ± 2.17 pg/mL) than the controls (0.93 ± 1.49 pg/mL; p = 0.003). The overall dose-response trend was significant (χ² = 6.12, df = 2; p = 0.047). No statistical difference was seen in age, gender and systemic disease distribution. A modest negative and significant correlation was seen between TNF-α level and number of antiglaucoma medications, an important clinical index of POAG severity. Moreover, logistic regression analysis showed that the risk of POAG was most significantly affected by TNF-α level and not by age and sex.

Conclusion

High systemic level of an inflammatory cytokine, TNF-α, is associated with POAG; however, its possible use as a biomarker for early glaucoma diagnosis and/or disease severity needs further investigation.

Elevated levels of plasma tumor necrosis factor alpha in patients with pseudoexfoliation glaucoma

Background

Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine, which plays a role in glaucomatous neurodegeneration. Based on the plausible role of inflammation in the pathogenesis of pseudoexfoliation glaucoma (PEG), we investigated whether there is any relationship between the levels of plasma TNF-α and PEG or any of its clinical indices in comparison to normal controls.

Methods

The study was designed as a retrospective analysis. Plasma samples from 49 PEG patients and 88 non-glaucomatous controls were evaluated for TNF-α levels using an enzyme-linked immunosorbent assay (ELISA). The assay was performed in duplicates on a biochemical/ELISA analyzer.

Results

The two study groups were similar in age, sex and systemic disease distribution. The mean TNF-α concentration was significantly higher in the PEG patients (5.54±4.58 pg/mL) than in the control subjects (0.93±1.49 pg/mL; 95% confidence interval [CI] =3.50–5.72; p=0.000). The overall dose–response trend was significant (χ²=57.07, df=2; p=0.000). A moderate positive and significant correlation was seen between TNF-α level and cup/disc ratio, an important clinical index for PEG. Besides, binary logistic regression analysis showed that the risk of PEG was most significantly affected by TNF-α level as compared to no association with age and sex. In receiver operating characteristic analysis, the area under the curve was 0.777 (95% CI =0.682–0.872) and statistically significant (p=0.000).

Conclusion

Elevated systemic levels of inflammatory marker, TNF-α, are associated with PEG and may possibly serve as a biomarker for undiagnosed early glaucoma and/or as a marker for disease progression.

Polymorphism rs10483727 in the SIX1/SIX6 Gene Locus Is a Risk Factor for Primary Open Angle Glaucoma in a Saudi Cohort

AIMS

Variant rs10483727 in the SIX1/SIX6 locus has been significantly associated with primary open angle glaucoma (POAG) in multiple ethnic groups. We conducted a case-control study to investigate the association between this variant and POAG in a Saudi cohort.

MATERIALS AND METHODS

Polymorphism rs10483727 was genotyped by using a TaqMan^® assay in 186 subjects comprising 92 unrelated POAG cases and 94 controls all of Saudi origin.

RESULTS

The "C" allele frequency was 0.33 and 0.45 among POAG cases and controls, respectively (odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.38-0.89; p = 0.013), suggesting a protective effect; and the "T" allele was associated with increased susceptibility to POAG (OR = 1.7, 95% CI = 1.11-2.58; p = 0.013). Genotype distribution was also significantly associated with POAG (χ² = 6.41, df = 2, p = 0.041). Endophenotype traits such as intraocular pressure and cup/disk ratio did not show any significant genotype distribution in POAG cases. A binary logistic regression analysis used to evaluate the effects of age, gender, and genotype on the likelihood of having POAG showed that genotype distribution (p = 0.012) significantly affected the disease outcome as compared with age (p = 0.055) and sex (p = 0.432).

CONCLUSION

The "T" allele of the rs10483727 polymorphism is an independent significant risk factor for POAG in the Saudi population.

Polymorphism rs11656696 in GAS7 Is Not Associated with Primary Open Angle Glaucoma in a Saudi Cohort

AIMS

To conduct a case-control study to investigate the association between the polymorphism rs11656696 located in the growth arrest-specific 7 gene (GAS7)on human chromosome 17p13.1 and primary open angle glaucoma (POAG).

METHODS

The polymorphism rs11656696 was genotyped using the TaqMan^® assay in 187 subjects comprising 92 unrelated POAG cases and 95 controls of Saudi Arabian origin.

RESULTS

Association analysis between cases and controls revealed no significant genotype distribution under additive (p = 0.225), dominant (p = 0.635), or recessive (p = 0.085) models. Moreover, the allele frequency distribution was also nonsignificant (p = 0.70). The minor "A" allele frequency was 0.35 and 0.41 among POAG cases and controls, respectively. In addition, specific clinical indices used to assess severity of glaucoma such as intraocular pressure (IOP), cup/disk ratio, and number of antiglaucoma medications also did not show any significant genotype distribution in POAG cases. Moreover, a binary logistic regression analysis did not show any significant effect of age, sex, or genotype on disease outcome.

CONCLUSION

Polymorphism rs11656696 is not associated with POAG nor any of its endophenotypic traits such as IOP and cup/disk ratio and is thus not a risk factor for POAG in this Saudi cohort.

Polymorphism rs547984 on human chromosome 1q43 is not associated with primary open angle glaucoma in a Saudi cohort

Background

To investigate the association between polymorphism rs547984, located in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene on human chromosome 1q43 and primary open angle glaucoma (POAG).

Method

Polymorphism rs547984 was genotyped using Taq-Man® assay in 185 subjects comprising of 90 unrelated POAG cases and 95 controls of Saudi origin.

Results

Association analysis between cases and controls revealed no significant genotype distribution under additive (p = 0.356), dominant (p = 0.517) and recessive (p = 0.309) models. Besides, the allele frequency distribution was also found to be non-significant (p = 0.70). The minor “A” allele frequency was found to be 0.49 and 0.50 among POAG cases and controls, respectively. In addition, specific clinical indices used to assess severity of glaucoma such as intraocular pressure (IOP), cup/disc ratio and number of anti-glaucoma medication also did not show any significant genotype distribution in POAG cases.

Conclusion

Polymorphism rs547984 is neither associated with any clinical indices important for POAG such as IOP and cup/disc ratio nor is a risk factor for POAG in the Saudi cohort.

Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci

Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide. Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS. To further elucidate the genetic basis of XFS, we collected a global sample of XFS cases to refine the association at LOXL1, which previously showed inconsistent results across populations, and to identify new variants associated with XFS. We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10^-14) through deep resequencing of XFS cases and controls from nine countries. A genome-wide association study (GWAS) of XFS cases and controls from 24 countries followed by replication in 18 countries identified seven genome-wide significant loci (P < 5 × 10^-8). We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). These findings provide biological insights into the pathology of XFS and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.

The Cytokine Interleukin-6 and the Chemokines CCL20 and CXCL13 Are Novel Biomarkers of Specific Endogenous Uveitic Entities

PURPOSE

The purpose of this study was to determine levels of the cytokines IL-1β, IL-6, IL-21, IL-22, and IL-23 and the chemokines CXCL13, CCL19, CCL20, and CCL21 in aqueous humor (AH) samples from patients with specific uveitic entities.

METHODS

Paired serum samples (n = 13) and AH samples (n = 111) from patients with active idiopathic granulomatous uveitis (IGU) or with uveitis associated with HLA-B27-related inflammation, Behçet's disease (BD), Vogt-Koyanagi-Harada (VKH) disease, or sarcoidosis and control patients were analyzed in two different multiplex assays.

RESULTS

Cytokines IL-1β, IL-21, IL-22, and IL-23 were not detected in any AH sample. Chemokine CCL21 concentrations in serum were significantly higher than those in AH. CCL19 levels in AH and serum were not significantly different. Levels of CCL20 and CXCL13 in AH were significantly higher than those in serum. IL-6 was not detected in serum samples. IL-6 AH levels were significantly higher in patients with HLA-B27-associated uveitis and in BD patients than in patients with VKH disease, sarcoidosis, and IGU (P < 0.0001). CCL20 AH levels were significantly higher in HLA-B27-associated uveitis than in BD, VKH, sarcoidosis, and IGU (P = 0.001), whereas CXCL13 AH levels were significantly higher in VKH disease and IGU than in HLA-B27-associated uveitis, BD, and sarcoidosis (P = 0.007).

CONCLUSIONS

IL-6-driven immune responses are more potent in HLA-B27-associated uveitis and BD than in VKH disease, sarcoidosis, and IGU. CCL20 appears to be a specific biomarker of HLA-B27-associated uveitis, whereas CXCL13 appears to be a biomarker of VKH disease and IGU. Our findings suggest that IL-6, CCL20, and CXCL13 could serve as drug targets for treatment of specific clinical entities of endogenous uveitis.

Association of total antioxidants level with glaucoma type and severity

Objectives:

To compare the mean total antioxidant status (TAS) among 3 glaucoma types, namely: pseudoexfoliation glaucoma (PEG), primary open angle glaucoma (POAG), and primary angle closure glaucoma (PACG), and study its potential association with various clinical glaucoma-parameters.

Methods:

In this case-control study, plasma samples were obtained between September 2013 and October 2014 from 340 glaucoma patients (PEG [n=54]; POAG [n=147]; PACG [n=139]), and 351 controls of matching age, gender, ethnicity, and 5 different systemic co-morbidities from King Abdulaziz University Hospital, Riyadh, Saudi Arabia. The TAS in all samples was determined by a colorimetric-based assay.

Results:

The mean±standard deviation of TAS was significantly lower among cases: 0.77±0.32 than controls: 1.1±0.22, p<0.0001. Moreover, the TAS levels were significantly different across the 3 types of glaucoma: 0.86±0.24 in PEG, 0.47±0.32 in POAG, and 0.98±0.41 in PACG (all p<0.0001). In addition, there was a significant correlation between TAS and age at onset (Pearson correlation coefficient [R] 0.17, p<0.0001), cup/disc ratio (R: -0.13, p=0.004), and number of anti-glaucoma medications (R: -0.16, p=0.001).

Conclusion:

Our findings provide evidence that plasma TAS levels are decreased in patients with glaucoma, more so in POAG and PEG than PACG, supporting the hypothesis that decreased antioxidative defense and/or increased oxidative stress may have a critical role in the pathogenesis of glaucoma.

Polymorphism rs7555523 in transmembrane and coiled-coil domain 1 (TMCO1) is not a risk factor for primary open angle glaucoma in a Saudi cohort

Background

We investigated whether polymorphism rs7555523 (A > C) in human transmembrane and coiled-coil domain 1 (TMCO1) gene is a risk factor for primary open angle glaucoma (POAG) in a Saudi cohort.

Methods

A cohort of 87 unrelated POAG cases and 94 control subjects from Saudi Arabia were genotyped using Taq-Man® assay. The association of genotypes with POAG and other glaucoma specific clinical indices was investigated.

Results

The genotype and allele frequency of polymorphism rs7555523 at TMCO1 did not show any statistically significant association with POAG as compared to controls. The minor allele frequency was 0.103 in cases and 0.085 in controls. Except for awareness of glaucoma (p = 0.036), no significant association of genotypes were seen with glaucoma specific clinical indices such as intraocular pressure (IOP), cup/disc ratio and number of anti-glaucoma medications used. Binary logistic regression analysis (adjusted for age and gender) showed that age was a significant indicator for the development of glaucoma in this group (adjusted odds ratio = 1.2; 95 % confidence interval = 1.078–1.157; p < 0.001).

Conclusion

Our study was unable to replicate the findings of previously reported association for polymorphism rs7555523 in TMCO1 with POAG and related clinical indices such as IOP and cup/disc ratio indicating that this variant is not a risk factor for POAG in the Saudi cohort.

Analysis of Polymorphism rs1900004 in Atonal bHLH Transcription Factor 7 in Saudi Patients with Primary Open Angle Glaucoma

AIMS

To investigate the association between the rs1900004 polymorphism in the atonal bHLH transcription factor 7 (ATOH7) gene and primary open angle glaucoma (POAG) in Saudi patients.

METHODS

Eighty-seven unrelated POAG cases and 94 unrelated control subjects of Saudi origin were genotyped utilizing a TaqMan^® assay. The association between mutant genotypes and POAG and its related clinical indices was investigated.

RESULTS

The genotype and allele frequencies of the polymorphism in ATOH7 did not show any statistically significant association with POAG compared to controls. The minor allele frequency was 0.32 in both cases and controls. None of the demographic, systemic diseases nor glaucoma-specific clinical indices such as intraocular pressure (IOP), cup/disc ratio, and number of antiglaucoma medication, showed any significant association with genotypes. Binary logistic regression analysis (adjusted for age and gender) showed that age was a marginally significant risk factor for the development of glaucoma (adjusted odds ratio = 1.1; 95% confidence interval = 1.079-1.158; p < 0.0001).

CONCLUSIONS

The study did not detect any direct link between genotype/allele frequency of rs1900004 in ATOH7 and POAG or its related clinical indices such as IOP and cup/disc ratio indicating that this polymorphism is not a risk factor for POAG in a Saudi cohort.

Analysis of Cyclin-Dependent Kinase Inhibitor-2B rs1063192 Polymorphism in Saudi Patients with Primary Open-Angle Glaucoma

AIMS

To investigate whether the polymorphism rs1063192 (A>G) in the cyclin-dependent kinase Inhibitor-2B (CDKN2B) gene is a risk factor for primary open-angle glaucoma (POAG).

METHOD

A case-control study was conducted wherein we genotyped 87 unrelated POAG cases and 94 control subjects from Saudi Arabia using the Taq-Man^® assay.

RESULTS

The minor allele frequency was 0.20 in POAG cases and 0.21 in controls. Both the genotype and allele frequencies were not significantly different between cases and controls. No significant association was found between genotypes and glaucoma clinical indices, except that the mutant homozygous genotype (G/G) was associated with the family history of glaucoma (p = 0.024).

CONCLUSION

Polymorphism rs1063192 in CDKN2B is not a risk factor for POAG in Saudi cohort.

Lack of Association Between Polymorphism rs4986791 in TLR4 and Primary Open-Angle Glaucoma in a Saudi Cohort

AIMS

To investigate whether single nucleotide polymorphism (SNP) rs4986791 (C>T) in the toll-like receptor 4 (TLR4) gene is a risk factor for primary open-angle glaucoma (POAG) in the Saudi population.

METHOD

A case-control study was performed to genotype a cohort of 85 POAG patients and 95 matched healthy controls utilizing TaqMan(®). The association between mutant genotypes and various POAG clinical indices were investigated.

RESULTS

The wild-type (C/C), heterozygous (C/T), and homozygous (T/T) genotypes were observed in 85.9%, 12.9%, and 1.2% POAG cases, respectively, compared to 91.6%, 8.4%, and none, respectively, among controls. The minor allele frequency was 0.076 in cases and 0.042 in controls. Both the genotype and allele frequency among POAG cases and controls did not vary significantly. With the exception of family history of glaucoma (p = 0.032), no significant association of genotypes was seen with age, intraocular pressure, cup/disc ratio, number of antiglaucoma medications, and other systemic comorbidities among the POAG cases.

CONCLUSION

We did not detect any direct association between genotypes or allele frequencies of SNP rs4986791 in the TLR4 gene and POAG.

Analysis of toll-like receptor rs4986790 polymorphism in Saudi patients with primary open angle glaucoma

BACKGROUND

To investigate whether SNP rs4986790 in toll-like receptors (TLRs) is a risk factor for primary open angle glaucoma (POAG) in a Saudi population.

MATERIALS AND METHODS

A cohort of 85 unrelated POAG patients and 95 unrelated control subjects from Saudi Arabia were genotyped utilizing Taq-Man® assay. The association between mutant genotypes and various clinical indices important for POAG was investigated.

RESULTS

Among cases, the normal pattern (A/A) was detected in 70 (82.4%) of the subjects, A/G in 14 (16.5%) and G/G in one subject only (1.2%). Among controls, prevalence of the genotype (A/A) was detected in 86 (90.5%), the (A/G) genotype in 8 (8.4%) and homozygous mutated genotype (G/G) in 1 (1.1%) subjects. Comparing cases to controls, the odds ratio of having heterozygous mutation (A/G) was 2.15 [95% CI: 0.853-5.417], which was not significant (p = 0.114). The odds ratio of having homozygous mutation (G/G) was 1.22 [95% CI: 0.075-19.99], which was statistically non-significant (p = 0.568). Likewise, the presence of the mutated allele (G) was non-significantly different between cases and controls (p = 0.154). Comparing cases to controls as regards co-morbidity with other systemic diseases, there were no statistically significant differences between groups in all assessed diseases except for a family history of glaucoma (p = 0.014) Conclusions: In conclusion, we could not detect any direct link between genotypes or allele frequencies of SNP rs4986790 in the TLR4 gene and POAG. In contrast, genotype (A/A) may be protective against POAG especially among individuals with no family history of glaucoma.

Analysis of Toll-Like Receptor 2 Polymorphism (rs5743704) in Saudi Patients with Primary Open-Angle Glaucoma

AIMS

To investigate whether the single-nucleotide polymorphism (SNP) rs5743704 in the toll-like receptor 2 gene is associated with primary open-angle glaucoma (POAG) or any of its clinical indices in a Saudi cohort.

METHOD

Ninety-five unrelated POAG cases and 95 controls of Saudi origin were genotyped utilizing a TaqMan(®) assay. The association between genotypes and various clinical indices important for POAG were investigated.

RESULTS

The genotypic and allelic frequencies among cases were not significantly different when compared to controls. The minor allele frequency was 0.021 in cases and 0.011 in controls. No significant association was seen with intraocular pressure and cup/disc ratio. However, carriers of the C/A genotype had higher number of anti-glaucoma medications compared to controls (p = 0.04).

CONCLUSION

SNP rs5773704 is not associated with POAG in a Saudi population. Despite sample size limitation, the association of the minor allele A with higher number of anti-glaucoma medications suggests a possible indirect role for this SNP in predicting disease severity.

A common variant near TGFBR3 is associated with primary open angle glaucoma

Primary open angle glaucoma (POAG), a major cause of blindness worldwide, is a complex disease with a significant genetic contribution. We performed Exome Array (Illumina) analysis on 3504 POAG cases and 9746 controls with replication of the most significant findings in 9173 POAG cases and 26 780 controls across 18 collections of Asian, African and European descent. Apart from confirming strong evidence of association at CDKN2B-AS1 (rs2157719 [G], odds ratio [OR] = 0.71, P = 2.81 × 10⁻³³), we observed one SNP showing significant association to POAG (CDC7–TGFBR3 rs1192415, OR_G-allele = 1.13, P_meta = 1.60 × 10⁻⁸). This particular SNP has previously been shown to be strongly associated with optic disc area and vertical cup-to-disc ratio, which are regarded as glaucoma-related quantitative traits. Our study now extends this by directly implicating it in POAG disease pathogenesis.

A common variant mapping to CACNA1A is associated with susceptibility to exfoliation syndrome

Exfoliation syndrome (XFS) is the most common recognizable cause of open-angle glaucoma worldwide. To better understand the etiology of XFS, we conducted a genome-wide association study (GWAS) of 1,484 cases and 1,188 controls from Japan and followed up the most significant findings in a further 6,901 cases and 20,727 controls from 17 countries across 6 continents. We discovered a genome-wide significant association between a new locus (CACNA1A rs4926244) and increased susceptibility to XFS (odds ratio (OR) = 1.16, P = 3.36 × 10(-11)). Although we also confirmed overwhelming association at the LOXL1 locus, the key SNP marker (LOXL1 rs4886776) demonstrated allelic reversal depending on the ancestry group (Japanese: OR(A allele) = 9.87, P = 2.13 × 10(-217); non-Japanese: OR(A allele) = 0.49, P = 2.35 × 10(-31)). Our findings represent the first genetic locus outside of LOXL1 surpassing genome-wide significance for XFS and provide insight into the biology and pathogenesis of the disease.

Total antioxidant level is correlated with intra-ocular pressure in patients with primary angle closure glaucoma

Background

To evaluate total antioxidant status (TAS) in the plasma of primary angle closure glaucoma (PACG) patients and to compare it to that of the control group. Additionally, we aim to investigate the association of various PACG clinical indices with TAS level.

Methods

Plasma samples were obtained from 139 PACG patients and 149 glaucoma-free controls of matching age, sex, and ethnicity. TAS in all samples was determined by spectrophotometric and enzyme-linked immunosorbent assay methods. We studied the possible association of the TAS level with various clinical indices relevant to PACG.

Results

The mean (±SD) total antioxidant (TAS) value was almost similar in patients 1 (±0.22) compared to controls 0.97 (±0.43); p = 0.345. Among cases, mean TAS concentration showed a statistically significant lower pattern among subjects with glaucoma onset at the age of ≤ 50 years (p = 0.037) and female subjects (p = 0.014) as well as having a family history of glaucoma (p = 0.010). Interestingly, a statistically significant inverse correlation was detected between TAS concentration and intra ocular pressure (IOP), (R = -0.14, p = 0.037).

Conclusions

The inverse correlation of TAS level with IOP, highlights TAS potential role as a predictive-marker for PACG-severity.

Decreased total antioxidants in patients with primary open angle glaucoma

PURPOSE

To evaluate total antioxidant status (TAS) in the plasma of primary open angle glaucoma (POAG) patients and to compare it to that of the control group. Additionally, we aim to investigate the association of various POAG clinical indices with TAS level.

MATERIALS AND METHODS

Plasma samples were obtained from 139 POAG patients and 148 glaucoma-free controls of matching age, sex, and ethnicity. TAS in all samples was determined by spectrophotometric and enzyme-linked immunosorbent assay methods.We studied the possible association of the TAS level with various clinical indices relevant to POAG.

RESULTS

The mean (±SD) total antioxidant (TAS) value was lower among patients: 0.47 (±0.32), than controls: 0.97 (±0.43) and this difference was statistically significant (p<0.0001). TAS concentration was not significantly associated neither with the level of intraocular pressure, nor with number of anti-glaucoma medications (p = 0.532 and 0.084 respectively). However, TAS level shows a trend towards reduction with increased severity of glaucoma presented in a reversed significant association with cup/disc ratio (p = 0.043).

CONCLUSIONS

Our findings provide evidence that TAS decreases in the plasma of POAG patients and that it may play a role in POAG pathogenesis. Association of TAS level with increased cup-to-disc ratio highlights TAS potential role as a predictive-marker for POAG-severity.

Association of SOD2 Mutation (c.47T > C) with Various Primary Angle Closure Glaucoma Clinical Indices

We investigated whether the c.47T>C polymorphism (SNP rs4880) in the manganese superoxide dismutase (SOD2) gene is a risk factor for primary angle closure glaucoma (PACG) in the Saudi population. Among cases (n=139), the prevalence of various genotypes were 25.9%, 46.8% and 27.3% for T/T, C/T and C/C genotypes respectively. This trend was similar in the controls (n=403); 22.6%, 50.1% and 27.3% for T/T, C/T and C/C respectively. The differences in genotype distribution were not statistically significant (p=0.391 and 0.682 respectively). The minor allele frequency was 50.7% in cases and 52.4% in controls; this difference was not statistically significant (p=0.676). Investigating the potential association between this SOD2 polymorphism and different clinical indices, there was a statistically significant difference among different genotype groups in terms of three important clinical indices for PACG; Mean age at onset, duration of onset to and the mean LogMAR visual acuity (p=0.041, 0.018 and 0.033 respectively). The three markers are highly associated prognostic factors to diseases severity. If our results are proven in larger cohort and in various populations, then this SNP may have potentiality to be used as an indicator for PACG severity.

A catalase promoter variant rs1001179 is associated with visual acuity but not with primary angle closure glaucoma in Saudi patients

Background

To Investigate whether the g.4760C>T polymorphism in the promoter region of the catalase gene (CAT) is a risk factor for primary angle closure glaucoma (PACG) in the Saudi population.

Methods

138 unrelated PACG patients and 403 unrelated control subjects from Saudi Arabia were genotyped for a single nucleotide polymorphism (SNP; rs1001179; g.4760C>T) utilizing Taq-Man® assay. The association between different genotypes and various clinical indices important for PACG was also investigated.

Results

The distribution of different genotypes was comparable between both study groups. The genotype “C/C” was predominant among cafses; 94 (68.1%) and controls; 289 (71.7%). Heterozygous genotype “C/T”, was present in 41 (29.7%) of cases and 103 (25.6%) of controls, where the homozygous variant genotype was present in only 3 (2.2%) of cases and 11 (2.7%) of the controls. The distribution of variant allele was similar in both study groups (p= 0.568). Interestingly, there was a trend of association between the type of the variant (homozygous variant, heterozygous and wildtype genotype) and one important parameter for PACG, which is visual acuity. The visual acuity increase was; 0.62 (±0.74), 0.88 (±0.88) and 1.27 (±0.95) in patients carrying the “C/C”, “C/T” and “T/T” genotypes respectively, which was statistically significant in both ANOVA and pairwise individual T tests (p = 0.022, 0.031 and 0.039) when compared to controls.

Conclusions

This variant is possibly associated with visual acuity in PACG patients and thus had the potential to be used as a parameter for assessing PACG severity.

Analysis of catalase SNP rs1001179 in Saudi patients with primary open angle glaucoma

PURPOSE

To investigate whether the g.4760C > T mutation in the catalase gene (CAT) is a risk factor for primary open angle glaucoma (POAG) in the Saudi population.

METHODS

A cohort of 225 unrelated POAG patients and 403 unrelated control subjects from Saudi Arabia were genotyped for a single nucleotide polymorphism (SNP; rs1001179; g.4760C > T) in the CAT gene utilizing Taq-Man® assay. The association between mutant genotypes and various clinical indices important for POAG was also investigated.

RESULTS

The distribution of different genotypes was comparable between both study groups. The genotype "C/C" was predominant among cases; 169 (75.1%) as well as among the controls; 289 (71.7%). As for the heterozygous mutated genotype "C/T", it was present in 52 (23.1%) of cases and 103 (25.6%) of controls, where the homozygous fully mutated genotype was present in only 4 (1.8%) of cases and 11 (2.7%) of the controls. The distribution of mutant allele was similar in both study groups (p = 0.218). Interestingly, there was a trend of association between the type of the mutation (homozygous versus heterozygous) and three clinical parameters important for predicting the severity of the disease. These parameters include mean age of onset, mean level of intraocular pressure (IOP) and mean months of duration of encountering glaucoma.

CONCLUSIONS

There were no statistically significant differences between cases and controls in terms of the different genotype distribution. This mutation is possibly associated with various clinical indices important for POAG and thus may be used as a parameter for assessing POAG severity, at least in this population.

Efficacy and safety of non-penetrating deep sclerectomy surgery in Saudi patients with uncontrolled open angle glaucoma

OBJECTIVE

To investigate the efficacy and safety of deep sclerectomy (DS) in Saudi patients with primary and secondary open-angle glaucoma (OAG).

METHODS

In this retrospective cohort study, a total of 194 eyes of 152 patients with OAG were consecutively enrolled to undergo DS with Mitomycin-C (MMC) at King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia between January 2002 and September 2010. Age at surgery, gender, type of glaucoma, operated eye, previous ocular surgery, type of implant, pre and final visit visual acuities, intraocular pressure (IOP), number of anti-glaucoma medications, optic nerve cup/disc ratio, and complications were recorded.

RESULTS

Cases were followed up to a mean of 60.9 (+/-49.7) months. The IOP reduced from a preoperative mean of 25.6 (+/-10.3) to final visit of 13.5 (+/-4), whereas the mean number of anti-glaucoma medication also reduced from 2.95 (+/-0.93) to 0.22 (+/-0.63), which was statistically significant (p<0.0001). Complete success was 82%, while overall success was 90.2%. Patients <50 years (p=0.003), high IOP (>/=21) at baseline (p=0.039), and being exposed to previous surgeries (p=0.047) were significant risk factors for failure, while combining cataract and converting to penetrating surgery have significantly improved the success rate (p=0.037).

CONCLUSION

Deep sclerectomy provides significant IOP reduction with low rate of visual threatening complications in Saudi patients with open angle glaucoma.

Lack of association of SNP rs4236601 near CAV1 and CAV2 with POAG in a Saudi cohort

PURPOSE

To determine the role of the recently discovered primary open angle glaucoma (POAG) single nucleotide polymorphism (SNP) rs4236601 near the caveolin-1 (CAV1) and CAV2 among patients and controls from Saudi Arabia.

METHODS

A cohort of 220 POAG patients and 405 control subjects from Saudi Arabia were genotyped for a SNP (rs4236601;g.2891 G>A) in the chromosome 7q31 locus near CAV1 and CAV2 using a standard polymerase chain reaction (PCR) and sequencing method.

RESULTS

The minor allele frequency (MAF) of rs4236601 was 0.3 in controls and 0.31 in POAG patients. We detected no statistical difference when we compared the allele frequencies between POAG patients and control subjects (p=0.699). Similarly, we detected no statistical difference in the frequency of the three possible rs4236601 genotypes between patients and controls. The p-values were 0.928 and 0.683 for heterozygous genotype (G/A) and homozygous mutant genotype (A/A), respectively. We found no statistically significant difference among patients with any of the three possible genotypes and various clinical indices important for glaucoma. Among patients with homozygous (A/A), the mean IOP was higher (21.4) compared to patients with G/G wildtype (20.4) and to patients with G/A genotype (18.5). However, this apparent difference did not reach the statistical significance threshold (p=0.062).

CONCLUSIONS

We were unable to detect this association in our POAG-patients from Saudi Arabia, suggesting that this risk factor may not have a strong effect in all populations. A founder effect may play a role in certain populations where the link was established.

Screening of CYP1B1 and LTBP2 genes in Saudi families with primary congenital glaucoma: genotype-phenotype correlation

PURPOSE

Primary congenital glaucoma (PCG) is a severe form of glaucoma that presents early in life. PCG is a clinical and genetic entity that is distinct from juvenile forms of glaucoma. Inheritance is usually autosomal recessive and therefore the disease might be more common in societies where consanguinity is high. We studied the prevalence of cytochrome P450, family 1, subfamily B, polypeptide 1 (CYP1B1) and latent-transforming growth factor beta-binding protein 2 (LTBP2) mutations in a group of Saudi PCG patients and attempted to correlate the mutation status with the disease severity.

METHODS

Genomic DNA was collected from 54 unrelated Saudi PCG families (74 patients) who were diagnosed as having PCG by standard ophthalmological examinations and screened for mutations in CYP1B1 and LTBP2 by sequencing. We also examined the effect of mutations on the phenotype of patients with PCG (phenotype-genotype correlation).

RESULTS

Mutations in CYP1B1 were identified in 41 (75.9%) of affected patients. No mutation in CYP1B1 was found in 13 (24.1%) affected persons. We detected a total of 13 mutations: 9 missense mutations (G61E, A119S, R390H, P437L, D441G, A443G, G466S, G466D, and R469W), 2 deletions (g.4238_4247del and g.7901_7913del), and 2 nonsense mutations (R355X and R444X). Two mutations, G466S and D441G, were novel. The G61E mutation was by far the most common mutation detected. PCG cases with CYP1B1 mutation(s) presented with a high degree of haze and greater cup/disc ratio than those with no mutation(s). Also, PCG cases with a mutation had higher post operative indices in terms of post operative haze and the need for anti-glaucoma medications. Additionally, the surgical success rate was higher 13/14 (92.9%) among cases without mutation than those with mutation 42/60 (70%). No mutation(s) were found in LTBP2 in any of the tested patients.

CONCLUSIONS

CYP1B1 mutations are the predominant cause of PCG in the Saudi Arabian population with G61E as the dominant disease-associated allele. PCG cases with a mutation had higher last postoperative visit indices in terms of postoperative haze and the need for anti-glaucoma medications. This will be a valuable parameter in predicting disease severity earlier on and might help in predicting the surgical outcome.

Decreased total antioxidants status in the plasma of patients with pseudoexfoliation glaucoma

PURPOSE

To evaluate total antioxidant status (TAS) in the plasma of pseudoexfoliation glaucoma (PEG) patients and to compare this level with a matching control group. Additionally, we aim to investigate the effect of the combined action of the lysyl oxidase-like 1 (LOXL1) mutation status with TAS level on the development of PEG.

METHODS

Plasma samples were obtained from 54 PEG patients and 54 controls of matching age, sex, and ethnicity. TAS in all samples was determined by spectrophotometric and enzyme-linked immunosorbent assay methods. The coding region of LOXL1, where it encompasses both single nucleotide polymorphisms (SNPs; rs1048661 and rs3825942), was sequenced.

RESULTS

The mean (±SD) total antioxidant (TAS) value was lower among patients: 0.87 (0.24), range 0.9-1.41 than controls: 1.07 (0.23), range 0.72-1.94, and this difference was statistically significant (p<0.0001: 95%CI: -0.295-0.114). Evaluating the impact of age, sex, and the mutation in addition to the mean TAS value in patients with PEG, a logistic regression analysis was conducted using diseased/not diseased as the outcome of interest (the dependent variable). Results show that, controlling for all other variables, mean TAS value (p<0.0001) and the mutation G/G in rs3825942 (p=0.041) are significant risk factors for PEG.

CONCLUSIONS

Our findings provide evidence that TAS decreases in the plasma of PEG patients, suggesting that TAS may have an important role in the pathogenesis of PEG. The combined effect of the "G" allele and the decreased TAS may contribute to the overall pathogenesis of PEG.

Susceptibility to primary angle closure glaucoma in Saudi Arabia: the possible role of mitochondrial DNA ancestry informative haplogroups

PURPOSE

In a previous preliminary analysis we reported that mitochondrial DNA (mtDNA) haplogroup R0a was significantly more frequent in primary angle closure glaucoma (PACG) Saudi patients than in healthy Saudi controls. This result prompted us to extend our work using a significant larger Saudi PACG cohort and more healthy controls.

METHODS

We sequenced the mtDNA regulatory hypervariable region-I (HVS-I) and coding regions, comprising haplogroup diagnostic polymorphisms, in 227 PACG Saudi patients and compared their haplogroup frequencies with those obtained from 186 matched healthy controls (free of PACG by examination) and from a large sample of 810 healthy Saudi Arabs representing the general Saudi population.

RESULTS

MtDNA Haplogroups R0a and J, the most abundant lineages in Saudi Arabia, were in significant higher frequencies in the PACG patients than in controls, while the widespread western Eurasian haplogroup U was associated with reduced risk to developing PACG.

CONCLUSIONS

Haplogroups R0a and J could be ancestry informative markers for PACG in the Saudi Arabian population. In addition, the western Eurasian haplogroup U may play a mild protective effect to this illness.

Mitochondrial DNA lineages of African origin confer susceptibility to primary open-angle glaucoma in Saudi patients

PURPOSE

We previously reported that certain mitochondrial DNA (mtDNA) polymorphisms in the coding region may be involved in the pathogenesis for primary open-angle-glaucoma (POAG). This encouraged us to extend our work and assess whether mtDNA diagnostic polymorphisms, defining geographically structured haplogroups, could be associated with the development of POAG.

METHODS

We sequenced the mtDNA regulatory hypervariable region-I (HVS-I) region and coding regions, comprising haplogroup diagnostic polymorphisms, in 176 POAG patients and 186 matched healthy controls (free of glaucoma by examination) of Saudi Arabia ascendancy. A large sample of 810 healthy Saudi Arabs representing the general Saudi population has also been included in the analysis. Assigning individuals into various mitochondrial haplogroups was performed using the nomenclature previously described for African and for Eurasian sequences.

RESULTS

African mtDNA haplotypes belonging to L haplogroups, excluding L2, confer susceptibility to POAG whereas the Eurasian haplogroup N1 was associated with reduced risk of developing POAG in Saudi Arabian population.

CONCLUSIONS

Saudi individuals with mtDNA of African origin are at higher risk of developing POAG. In addition, the mtDNA Eurasian haplogroup N1 may play a mild protective effect to this illness.