Molecular Vision 2024; 30:320-335
<http://www.molvis.org/molvis/v30/320>
Received 15 January 2024 | Accepted 03 October 2024 | Published 07 October 2024
Molecular Vision 2024; 30:320-335
<http://www.molvis.org/molvis/v30/320>
Received 15 January 2024 |
Accepted 03 October 2024 |
Published 07 October 2024
Ariunzaya Altankhuyag,1 Chimedlkhamsuren Ganbold,2 Bayarlakh Byambadorj,2 Suvd Tumurbaatar,2,3 Purevsuren Sodnomtseren,4 Uranchimeg Davaatseren,1 Sarantuya Jav2,3
1Department of Ophthalmology, Mongolian National University of Medical Sciences; 2Department of Molecular biology and genetics, Mongolian National University of Medical Sciences; 3Molecular sector, Institute of Biomedicine, Mongolian National University of Medical Sciences,; 4School of Pharmacy, Mongolian National University of Medical Sciences
Correspondence to: Sarantuya Jav, Department of Molecular Biology and Genetics, Molecular sector, Institute of Biomedicine, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia; Phone: (976) 9909 2771; email: sarantuya.j@mnums.edu.mn
Background: Age related macular degeneration (AMD) is a multifactorial disease caused by a combination of environmental and genetic factors. The prevalence of allele and genotypeof AMD-related genes is varied throughout the world due to racial and ethnic differences. Number of previous studies have shown that the polymorphisms in the ARMS2, CFH and VEGF-A genes are associated with AMD. In Mongolia, there is a lack of sufficient data on AMD development in its population and thus needs more studies on the topic. Therefore, it needs more studies about AMD development in the population. For this reason, we have investigated several specified polymorphisms in CFH, VEGF-A and ARMS2 genes to reveal a relationship with AMD and determine the prevalence of alleles and genotypes of the genes in Mongolian population.
Methods: Totally 161 AMD patients and 223 controls were enrolled in this case-control study. The polymorphisms in CFH, ARMS2 and VEGF-A were detected by using the methods of allele-specific polymerase chain reaction (ASPCR) and PCR based restriction fragment length polymorphism (RFLP). Statistical analysis were performed by STATA 13.0, SNPAlyze 9.0 and MDR 3.0.2.
Results: According to the study result, the characteristics of hypertension, constant-wearing sunglasses and anticoagulant medications in AMD group were significantly different from those in the control group. As for the dominant model, T allele of ARMS2 rs10490924 (cOR=4.45; 95% CI, 2.44-8.13, p<0.001, aOR=5.08; 95% CI, 2.70-9.59, p<0.001) was more frequent among patients with AMD in comparison with the control group. Also, G/G genotype of CFH rs800292 (cOR=11.61; 95% CI, 3.41-39.51, p<0.001, aOR=12.49; 95% CI, 3.47-44.91, p<0.001) and G/G genotype of CFH rs1065489 (cOR=4.19; 95% CI, 2.53-6.93, p<0.001, aOR=4.67; 95% CI, 2.71-8.05, p<0.001) were significantly higher in AMD group after Bonferroni correction. This result suggests that people who carrying the risk genotypes of these polymorphisms had an increased risk for AMD development. As for the models of three or more SNP interactions, the participants with any combinations of risk genotypes have 6 to 106-fold higher risk for AMD development. This result suggests that there is some positive-additive interaction existing between the genetic variants of ARMS2, CFH and VEGF-A genes for AMD development. Our study also revealed that the participants with hypertension and carrying G/G for rs1065489 in CFH gene or non G/G for rs10490924 in ARMS2 gene genotypes had 9 to 14 times higher risk for AMD development (cOR=9.05; 95% CI, 4.38-18.68, p<0.001, RERI=4.546; AP=0.502, S=2.298, cOR=13.98; 95% CI, 3.19-61.1, p<0.001, RERI=5.85; AP=0.419, S=1.821) with high level of significance. Moreover, it was found that the participants who avoided wearing sunglasses and had the G/G genotype of ARMS2 rs10490924 or G/G genotype of CFH rs800292 had an extremely higher risk for AMD development (p<.001).
Conclusions: In conclusion, it was observed that the combination of SNPs in ARMS2, CFH and VEGF-A genes increase the risk for AMD with 6 to 106-fold. Moreover, we found that the participants with hypertension and carrying the non G/G genotype of ARMS2 rs10490924 or the G/G genotype of CFH rs800292 had an extremely higher risk of AMD development.
According to the report of 2020 from World Health Organization (WHO), 2.2 billion people with various cause-related vision loss had been diagnosed throughout the World among which majority of cases was linked into the people aged over 50 [1]. Approximately 81% of people with vision impairment may be prevented from vision loss [2].
Age related macular degeneration (AMD) is an important cause of central vision loss which is more common in older people aged over 60 [3]. So far, it has been reported that approximately 50 million people has diagnosed with AMD in the world [4,5]. Clinically, AMD is classified into 2 forms, including dry and wet forms. The dry form of AMD is dominantly spread throughout the world and accounts for 80-85% of the all AMD cases. Although the wet form of AMD (or neovascular AMD) is less common in the patients diagnosed with AMD, however, 90% of the cases can cause severe form of vision loss [6,7].
AMD is a multifactorial neurodegenerative disease relating with a combination of environmental and genetic factors, and a contribution of age effect [8,9]. Importantly, body mass index (BMI) and smoking have been reported to be the most crucial risk factors of environment for AMD development [10-12]. Also, obesity was investigated to be associated with the disease. Moreover, alcoholic drink usage [13], some diet habits including high glycemic, and red and processed meat, fried food, refined grains and high-fat dairy [14], ultraviolet ray of the sun [15], and some medical conditions such as having hypertension [16] and diabetes [17], and variability of iris color [18] have been revealed to be linked to the development of AMD.
In recent years, many genetic studies have reported that several gene mutations and variations are associated with the pathogenesis of AMD [19,20]. In a review, Olga Sergejeva et al reported that 36 genes including complement factor H (CFH), complement factor B (CFB), human high temperature requirement serine protease A1 (HTRA1) and age-related maculopathy susceptibility 2 (ARMS2) are more likely to be associated with the development of AMD [21].
The polymorphisms in CFH are reported to be associated with the AMD [22]. rs1061170, rs800292 and rs1065489 polymorphisms in CFH increases complement activation in eye, which may increase the susceptibility of AMD onset. Also, the polymorphism rs10490924 in ARMS2 gene has been reported to be highly associated with pathogenesis of AMD, which is related to an indel mutation (del443ins54) [23]. Moreover, vascular endothelial growth factor (VEGF-A) gene was also reported to be most likely to associate with neovascular AMD development and its progression [24,25]. It was known that VEGF-A protein plays an important role in regulation of angiogenesis, vascular leakage and inflammation in the progression of neovascular AMD [26]. So far, several polymorphisms in VEGF-A such as rs833061, rs1413711 [27], rs2010963 [28], rs144854329, rs2146323 [29] and rs1570360 [30] have been investigated to discover the relationship with the progression of AMD.
In the world, the prevalence of allele and genotypic forms of the genes-related to AMD development is obviously different which can be explained by the involvement of genetic factors in racial and ethnic differences. Mongolia has a number of diagnosed cases of AMD, so it needs more studies on risk factors of AMD in the population, especially genetic variation studies. For this reason, we have investigated several specified polymorphisms in CFH, VEGF-A and ARMS2 genes to reveal a relationship with AMD and determine the prevalence of alleles and genotypes of the genes in Mongolian population.
Ethical approvals were obtained from the Medical Ethical Review Board of Mongolian National University of Medical Sciences (Approval numbers: Nº2018/3-11). According to the survey approval from the Ethics Committee, written consents from all adults of over 50 years old were obtained.
A case-control study was designed as hospital-based and conducted from 2018 to 2019. 161 patients with AMD were participated for the case group, who had been referred to “Bolor Melmii” Hospital of Ulaanbaatar, Mongolia. The control group consisted of healthy volunteers from Mongolia-Japan Hospital of Mongolian National University of Medical Science, Ulaanbaatar, Mongolia.
Study participants were sampled by using a non-probability sampling method. The population size for the case and control study was estimated in accordance with the population of over 50 years old in Ulaanbaatar, Mongolia. The population size in Ulaanbaatar was 107029 (Report from National Statistics Office of Mongolia, 2019). According to the population aged over 50 years, the calculated sample size in this study was 116 participants in case group and 223 participants in control group.
Several inclusion criteria were used to determine participation allowance for the case and control study groups. For the case group, the participants were allowed if they were matched with the following statements. 1) People aged over 50 years, 2) No cataract or early cataract was diagnosed, 3) Media in the eye should have no opacities, 4) Drusen are 63 µm and above for dry AMD 5) Visual acuity should be 0.1 and above, 6) Vision capacity should be 0.05 and above if having swelling and exudative form of AMD, 7) Participants should gave informed consent. For the control group, the participants were allowed if they were matched with the following statements. 1) People aged over 50 years, 2) No cataract or early cataract was diagnosed, 3) Media in the eye should have no opacities, 4) No AMD was diagnosed and 5) Participants should gave informed consent.
The participants were excluded if they had a glaucoma, diabetic retinopathy, other maculopathy and retinopathy. Foreign national was not allowed to participate in the study. Also, those who did not give consent were excluded.
A paper-based questionnaire written in Mongolian was adopted by the research team members. It was taken from each participants to clarify the demographics (age, gender, body mass index (BMI) and Living residence), occupational and educational status and determine the environmental risk factors for AMD development. The questions were either closed-ended or dichotomous and the explanations were given when necessary.
3 ml of blood sample was collected from peripheral blood of study participants under strict infection control. Blood sample was centrifuged at a speed of 670 ×g for 20 min to isolate the white blood cells. The sample was transported in dry ice to the laboratory.
DNA was extracted by using a genomic DNA extraction kit according to the manufacturer’s instruction (Cat. No. K-3032G, Bioneer, South Korea). The yield and purification of DNA for each sample were tested by Nano-drop spectrophotometer.
The polymorphisms in CFH, ARMS2 and VEGF-A were detected by using the methods of allele-specific polymerase chain reaction (ASPCR) and PCR based restriction fragment length polymorphism (RFLP) which were performed as previously described [31-35]. The list of methods, primers, restriction enzymes and fragment length was summarized in Appendix 1. PCR reactions were performed with Accupower PreMix kit (Cat. No. K-2036, Bioneer, South Korea). The amplified DNA products and digested fragments were detected by agarose-gel electrophoresis and visualized by UV transilluminator.
Analyses were performed using STATA 13.0 (StataCorp, College Station, TX), Microsoft Excel (Microsoft Corporation, Redmond, WA) and SNPalyze software. Comparisons of qualitative variables were analyzed by Pearson’s chi-square test (χ2) for 2x2, 2x3 or 2×4 contingency tables and the Fisher’s exact test. For all univariate analysis, a p-value of 0.05 was considered statistically significant. A logistic regression model was used to evaluate the risk factors for AMD development. Crude (cOR) for the univariate model and adjusted odds ratios (aOR) for the multivariate model with a 95% confidence interval (CI) were calculated by logistic regression. SNPalyze 9.0 software was applied to detect and compare the frequency of haplotypes in each study groups. A basis of frequencies of allele and genotype of the polymorphisms, a suitable model was firstly chosen from 4 common models including dominance, recessive, over-dominance and co-dominance, and then the risk assessment was conducted for AMD development [36]. A calculation technique adopted by Noboyuki Horita et al was applied in this study [36]. The interaction of risk factors for AMD development was evaluated using relative excess risk due to interaction (RERI), synergy index (S) and proportion attributable of interaction (AP) variables developed by Knol MJ et al. [37] P values for multivariate model was corrected by Bonferronni correction. The statistical power was calculated by post-hoc test, to estimate the level of association.
161 patients with AMD and 223 healthy people were enrolled in our study groups. 95 patients with dry AMD and 66 patients with wet AMD were participated in case group. The baseline demographic characteristics for the study groups are summarized in Table 1. No significant differences were observed for age, gender, BMI, education level, occupational exposure to dust and smoking between the study groups. Interestingly, the characteristics of hypertension, constant-wearing sunglasses and anticoagulant medications in AMD group were significantly different from those in the control group.
To clarify the characteristic difference in the study groups, odd`s ratio and significance were calculated in univariate and multivariate model for above mentioned variables. For the anticoagulant users, an increased risk for AMD was found in univariate regression. According to the univariate and multivariate logistic regression analysis, significantly higher risk of AMD was observed for participants with hypertension (cOR=2.05; 95% CI, 1.31-3.19, p=0.001, aOR=2.01; 95% CI, 1.28-3.17, p=0.039). Also, it was observed that constant-wearing sunglasses were significantly lowering the risk (cOR=0.33; 95% CI, 0.19-0.59, p<0.001, aOR=0.34; 95% CI, 0.19-0.60, p<0.001) for AMD development (Table 2)
Distribution of the genetic polymorphisms among a population can be explained by estimating the Hardy-Weinberg equilibrium. According to the Hardy-Weinberg theory, the distribution of polymorphisms of CFH, ARMS2 and VEGF-A genes was calculated and some explainable differences were found in our study groups. The prevalence data of alleles and genotypes of rs10490924 in ARMS2 gene, rs1061170, rs1065489 and rs800292 in CFH gene, and rs833061 and rs2146323 in VEGF-A gene showed significant differences in AMD group as compared to control group.
By univariate and multivariate regression, it was found that G allele of CFHrs1065489 (cOR=4.19; 95% CI, 2.53-6.93, p<0.001, aOR=4.67; 95% CI, 2.71-8.05, p<0.001) and G allele of CFHrs800292 (cOR=11.61; 95% CI, 3.41-39.51, p<0.001, aOR=12.49; 95% CI, 3.47-44.91, p<0.001) were associated with AMD development according to the recessive model after Bonferroni correction. As for the dominant model, T allele of ARMS2rs10490924 (cOR=4.45; 95% CI, 2.44-8.13, p<0.001, aOR=5.08; 95% CI, 2.70-9.59, p<0.001) was associated with increased risk of AMD compared with the control group after Bonferroni correction. This result suggests that people who carrying the risk genotypes above mentioned had an extremely higher risk for AMD development as compared to the participants without any of these genotypes. However, G/T genotype of CFHrs1065489 (cOR=0.30; 95% CI, 0.19-0.46, p<0.001, aOR=0.29; 95% CI, 0.18-0.47, p<0.001) had produced a protective effect for AMD development and it would be defined as an incomplete dominant model. Comparisons of all allele and genotype frequencies between the groups were shown in Table 3 and Table 4. We compared the frequencies of all alleles and genotypes between dry and wet AMD groups and control group but found no association.
Entropy-based gene-gene interaction was estimated in our study to reveal the functional relationship of the genes for AMD development and the gene-gene interaction network was depicted in Figure 1. The polymorphisms of rs10490924 (7.58%) in ARMS2 gene, rs1065489 (6.82%), rs800292 (5.81%) and rs1061170 (2.13%) in CFH gene and rs2146323 (1.01%) in VEGF-A gene were found to contribute the high-independent effect (>1.0%) among all the genetic factors. High and moderate degrees of synergistic interaction were detected between VEGF-A gene polymorphisms such as rs833061, rs144854329, rs1413711, rs2146323 and rs1570360. In addition, the interactions between other polymorphisms were detected as redundancy.
SNP x SNP interaction analysis was performed among all polymorphisms. The best interaction models identified MDR from 10-fold cross-validation for AMD were listed in Table 5. Significant associations were found in the frequencies of combination genotypes of rs10490924 in ARMS2 gene and rs1065489CFH gene between the case and control groups. It was found that the participants carrying both of non G/G of rs10490924 and G/G of rs1065489 (cOR=4.52; 95% CI, 2.93-6.99, p<0.001) genotypes have a higher risk for AMD development as compared to the participants without any risk genotypes. According to the models for three or more SNP interactions (Table 5), the participants who carrying any combinations of risk genotypes have 6 to 106-fold higher risk for AMD development in comparison with others. This result suggests that there is some positive-additive interaction existing between the genetic variants of ARMS-2, CFH and VEGF-A genes for AMD development risk.
In our study, stepwise analyses were applied to focus on revealing the relationship between the genetic polymorphisms and the risk factors associated with AMD development. According to the results, we have found some significant interactions between the polymorphisms and the risk factors. It was revealed that the participants with hypertension and carrying G/G for rs1065489 in CFH gene or non G/G for rs10490924 in ARMS2 gene genotypes had 9 to 14 times higher risk for AMD development (cOR=9.05; 95% CI, 4.38-18.68, p<0.001, RERI=4.546; AP=0.502, S=2.298, cOR=13.98; 95% CI, 3.19-61.1, p<0.001, RERI=5.85; AP=0.419, S=1.821) with high level of significance. Interestingly, it was also found that the participants who avoid wearing sunglasses and having with non G/G for rs10490924 in ARMS2 gene or G/G for rs800292 in CFH gene genotypes had extremely higher risk for AMD development (p<0.001).
As a result, there are some haplotypes of CFH and VEGF-A, has found as risk or protective effect factors. The frequency of C-G-G (cOR=2.13; 95% CI, 1.41-3.24, p<0.001) haplotype of CFH, T-C-G-Del-C-G (cOR=1.74; 95% CI, 1.27-2.38, p=0.001) and C-T-C-Ins-A-G (cOR=2.03; 95% CI, 1.20-3.44, p=0.004) haplotypes of VEGF-A, were higher in AMD group. Contrariwise, we found that people who had T-T-A (cOR=0.39; 95% CI, 0.27-0.57, p<0.001) haplotype of CFH, T-T-G-Del-C-G (cOR=0.16; 95% CI, 0.04-0.69, p=0.003) and T-C-G-Del-A-G (cOR=0.27; 95% CI, 0.08-0.94, p=0.024) haplotypes of VEGF-A, significantly lower risk for AMD. We assessed the pairwise linkage disequilibrium for rs1061170, rs1065489, and rs800292 of CFH gene, rs833061, rs1413711, rs2010963, rs144854329, rs2146323 and rs1570360 of VEGF-A gene using the parameter of r2. Linkage disequilibrium between rs833061 and rs1413711 (D` = 0.889, r2 = 0.637), rs833061 and rs144854329 (D` = 0.931, r2 = 0.774) observed with high D` value with the pairwise r2 (Table 6, Table 7, Table 8 and Table 9).
AMD is now a well-recognized medical condition that can be a leading cause of hazy or no vision in the visual field center older aged population [38-40]. It was known that the development of AMD would be explained by a variety of causes including environmental factors, genetic factors, individual and health problems [8,41,42]. In recent years, the interactions of risk factors or causes for AMD development have been extensively investigated throughout the world to discover the authentic basis of triggering the disease among the population. Therefore, our study was focused on detecting the associations between the genetic, environmental and individual risk factors for development of AMD.
For this purpose, we have chosen several genetic factors such as single nucleotide polymorphisms in ARMS2, CFH and VEGF-A genes and individual factors such as wearing sunglasses and smoking, and medical conditions such as hypertension and using anti-coagulant medication to investigate the interactions and effects between a variety of risk factors on pathogenesis for AMD development in this study. In the current study, a total of 384 participants were allowed to participate in, in which 161 patients with AMD were in the case group and 223 healthy people were in control group.
In accordance with our study results, it has been detected that the individual and health condition-related risk factors were related to the pathogenesis for AMD development. As for the arterial hypertension, it was confirmed that it increases the risk of AMD in our study. The contribution of arterial hypertension in pathogenesis of AMD development was elucidated by damaging retinal vessels and vascular dysfunction [43,44]. Also, we have found that anticoagulant medication was a significant risk factor for AMD development. The role of anticoagulant medication in the pathogenesis of AMD would be related to a massive intraocular hemorrhage developed in the patients with exudative AMD [45,46]. There are many evidence that wearing sunglasses can increase the chance of not developing AMD due to protection from free radicals originated by sun exposure [47-49]. In our study, it was also demonstrated that constant-wearing sunglasses were significantly lowering the risk of AMD.
In the current time, there are many efforts on AMD development to figure out the pathogenesis and consider the prevention issues in further. Many studies have been conducted to find authentic causes or risk factors and then revealed some SNPs as genetic markers for AMD development. Sven Micklisch et al reported that rs10490924 in ARMS2 gene were highly associated with AMD development, which can influence on a complement activator to become deficient [50]. Montserrat et al found that rs1061170, rs1065489 and rs800292 in CFH gene increased the risk of AMD [51]. In this study, the alleles and genotype prevalence of rs10490924 in ARMS2 gene, rs1061170, rs1065489 and rs800292 in CFH gene, and rs833061 and rs2146323 in VEGF-A gene have been detected. There were some significant differences observed in AMD group as compared with the control group. Hence, it indicated that genetic risk factors might be an important role on AMD development.
In early studies, it was observed that the prevalence of AMD was different due to variations of ethnicity and races of the world population [52], especially it was related to the risky allele frequencies of rs10490924 in ARMS2 gene, and rs1061170 and rs800292 in CFH gene [53-57]. Several studies reported that risky T allele of rs10490924 in ARMS2 gene was more frequently spread in Asian population as compared to Caucasians. In our study, the risky T allele of rs10490924 in ARMS2 gene was detected a highly frequented allele in the population of Mongolia (RAF=0.714, n=230) as comparison with those studies in South Korea (RAF=0.609, n=167) [53], Japan (RAF=0.609, 94) [54] and China (RAF=0.649, n=157) [56]. It indicated that the pathogenesis of AMD development in this geographic region might be more related to the risky T allele of rs10490924 in ARMS2 gene. So far, the role of ARMS2 protein in the pathogenesis for AMD development is elucidated by weakening the function of mitochondria-rich retinal photoreceptor cell due to reduced level of the protein [58,59]. Also, Shughoury et al, reported that rs10490924 T allele predicted to result serine amino acid at 69th, creates a new phosphorylation site and breaks an alpha-helix. This structure and functional alteration may play a role in oxidative stress and damage to the retina [60]. However, the function of the protein for AMD development is still unclear. As for the risky C allele of rs1061170 and risky G allele of rs800292 in CFH gene, it was found more frequently in European population (35%) while it was comparably lower in Asian population (5%) [51,61]. Tortajada A. et al, reported rs800292 G (Val62) allele may contribute to lack binding CFH to C3b and thereby leading to increase complement activation. CFH dysfunction affected by the risk alleles may lead to the development of localized chronic inflammation in the retina [62]. In the current study, the frequencies of the risky C allele of rs1061170 and risky G allele of rs800292 in CFH gene were also relatively lower in Mongolian population. It suggested that these alleles are rare but strong risk factors for AMD development in Mongolian population.
In the current time, genome-wide association studies (GWAS) revealed that more than 52 independent SNPs at 34 genetic loci have strong associations with AMD development [63]. Several studies reported that there are profoundly correlative effects between AMD-related genes [64-66]. Moreover, some studies had proved that no direct association between risk alleles of CFH and ARMS2 was observed for the pathogenesis of AMD [23]. In a study, it was also reported that total genetic risk factors wasn’t common for AMD development in individuals with aged 90 and over [67]. In our study, it was found that the participants who carrying any combinations of SNPs in ARMS2, CFH and VEGF-A genes have 6 to 106-fold higher risk for AMD development in comparison with the control groups. Therefore, our study suggests that direct or non-direct associations between AMD-related genes would be found and may enlighten the pathogenesis for AMD development.
So far, many studies have reported that the risk genes and other risk factors are combined to trigger the pathogenesis for AMD development. Tina Schick at el conducted an interaction analysis on age and polymorphisms for AMD and revealed strong age-related effects for rs570618 and rs3750846 [67]. Recently, it was also reported that a combination of risk alleles from ARMS2 A69S and hypertension increases the risk of nAMD [68]. We have also found some significant interactions between the polymorphisms and the risk factors for AMD development. Our study revealed that the participants with hypertension and carrying G/G for rs1065489 in CFH gene or non-G/G for rs10490924 in ARMS2 gene genotypes had 9 to 14 times higher risk for AMD development with high level of significance. Interestingly, it was also found that the participants who avoid from wearing sunglasses and having with non G/G for rs10490924 in ARMS2 gene or G/G for rs800292 in CFH gene genotypes had extremely higher risk for AMD development. Hence, these results suggested that both of genetic and environmental risk factors play a significant role in the pathogenesis for AMD development.
In this study, we have proposed some strong evidence on understanding and augmenting the known pathogenesis in next step for AMD development. A risky T allele of rs10490924 in ARMS2 gene is the most frequent allele for AMD diagnosed patients in this geographic region. Also, we found rs800292 G and rs1061170 C alleles have associated with increased risk of AMD. In addition, our study has found that there are direct and non-direct interactions between AMD-related genes, and both of genetic and environmental risk factors are related to the pathogenesis for AMD development. In further studies, it needs more investigations to reveal the authentic mechanisms for AMD development.
In conclusion, our findings indicated that risky T allele of rs10490924 in ARMS2 gene for AMD development was detected a highly frequented allele in the population of Mongolia (RAF=0.714, n=230). Also, it was observed that the combination of SNPs in ARMS2, CFH and VEGF-A genes increase the risk for AMD with 6 to 106-fold. Moreover, it was found that the participants who have hypertension or avoid wearing sunglasses and having with non G/G for rs10490924 in ARMS2 gene or G/G for rs800292 in CFH gene genotypes had extremely higher risk for AMD development.
We extend our gratitude to the medical staff at Department of Molecular biology and Genetics and Department of Ophthalmology of Mongolian National University of Medical Sciences who collaborated with us in conducting the present study.