HTRA1 promoter polymorphism and risk of age-related macular degeneration: a meta-analysis

Elastin turnover in ocular diseases: A special focus on age-related macular degeneration

The extracellular matrix (ECM) and its turnover play a crucial role in the pathogenesis of several inflammatory diseases, including age-related macular degeneration (AMD). Elastin, a critical protein component of the ECM, not only provides structural and mechanical support to tissues, but also mediates several intracellular and extracellular molecular signaling pathways. Abnormal turnover of elastin has pathological implications. In the eye elastin is a major structural component of Bruch's membrane (BrM), a critical ECM structure separating the retinal pigment epithelium (RPE) from the choriocapillaris. Reduced integrity of macular BrM elastin, increased serum levels of elastin-derived peptides (EDPs), and elevated elastin antibodies have been reported in AMD. Existing reports suggest that elastases, the elastin-degrading enzymes secreted by RPE, infiltrating macrophages or neutrophils could be involved in BrM elastin degradation, thus contributing to AMD pathogenesis. EDPs derived from elastin degradation can increase inflammatory and angiogenic responses in tissues, and the elastin antibodies are shown to play roles in immune cell activity and complement activation. This review summarizes our current understanding on the elastases/elastin fragments-mediated mechanisms of AMD pathogenesis.

Polymorphism rs11200638 enhanced HtrA1 responsiveness and expression are associated with age-related macular degeneration

OBJECTIVES

To investigate the role of polymorphism rs11200638 of high-temperature requirement factor A-1 (HtrA1) gene in the pathogenesis of age-related macular degeneration (AMD).

METHODS

Cultured adult retinal pigment epithelial cells (ARPE-19) expressing HtrA1 gene were treated with H2O2 or lipopolysaccharides (LPS) and analysed using western blot and quantitative polymerase chain reaction to illustrate the effects of oxidative and inflammatory stress on HtrA1 gene expression. Luciferase reporter plasmid driven by HtrA1 promoter with either normal allele G or risk allele A at SNP rs11200638 was transfected to ARPE-19 cells to investigate the effect of the G/A variation on HtrA1 promoter activity. The effects of HtrA1 overexpression on ARPE-19 cells were analysed with respect to percentage of cell proliferation inhibition and cell apoptosis.

RESULTS

HtrA1 expression was significantly increased with LPS or H2O2 stimulations (p < 0.05). In ARPE-19 cells, HtrA1 promoters (-1 to -2175 bp from translation starting point) with risk allele A or normal G at rs11200638 did not show statistically significant differences in their luciferase reporter expression (p = 0.054425173), however, both promoters showed a persistent trend of higher luciferase expressions after 100 ng/ml LPS treatment. The luciferase expression level was significantly greater in the promoter with risk A when compared to that with normal G. Overexpression of HtrA1 resulted in apoptosis of ARPE-19 cells with 53.8 ± 1.6% of proliferation inhibition (p < 0.01).

CONCLUSIONS

Risk haplotype A at rs11200638 significantly increased the responsiveness of HtrA1 promoter to inflammation and subsequently enhanced HtrA1 expression. HtrA1 overexpression induced ARPE-19 apoptosis and growth inhibition, relevant to pathogenesis of AMD.

The levels of the serine protease HTRA1 in cerebrospinal fluid correlate with progression and disability in multiple sclerosis

BACKGROUND

High Temperature Requirement Serine Protease A1 (HTRA1) degrades extracellular matrix molecules (ECMs) and growth factors. It interacts with several proteins implicated in multiple sclerosis (MS), but has not previously been linked to the disease.

OBJECTIVE

Investigate the levels of HTRA1 in cerebrospinal fluid (CSF) in different subtypes of MS and brain tissue.

METHODS

Using ELISA, HTRA1 levels were compared in CSF from untreated patients with relapsing-remitting MS (RRMS, n = 23), secondary progressive MS (SPMS, n = 26) and healthy controls (HCs, n = 26). The effect of disease modifying therapies (DMTs) were examined in both patient groups. Cellular distribution in human brain was studied using immunochemistry and the oligointernode database, based on a single-nuclei RNA expression map.

RESULTS

HTRA1 increased in RRMS and SPMS compared to HCs. DMT decreased HTRA1 levels in both types of MS. Using ROC analysis, HTRA1 cut-offs could discriminate HCs from RRMS patients with 100% specificity and 82.6% sensitivity. In the brain, HTRA1 was expressed in glia and neurons.

CONCLUSION

HTRA1 is a promising CSF biomarker for MS correlating with disease- and disability progression. Most cell species of the normal and diseased CNS express HTRA1 and the expression pattern could reflect pathological processes involved in MS pathogenesis.

Matrix Metalloproteinases in Age-Related Macular Degeneration (AMD)

Age-related macular degeneration (AMD) is a complex, multifactorial and progressive retinal disease affecting millions of people worldwide. In developed countries, it is the leading cause of vision loss and legal blindness among the elderly. Although the pathogenesis of AMD is still barely understood, recent studies have reported that disorders in the regulation of the extracellular matrix (ECM) play an important role in its etiopathogenesis. The dynamic metabolism of the ECM is closely regulated by matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs). The present review focuses on the crucial processes that occur at the level of the Bruch’s membrane, with special emphasis on MMPs, TIMPs, and the polymorphisms associated with increased susceptibility to AMD development. A systematic literature search was performed, covering the years 1990–2020, using the following keywords: AMD, extracellular matrix, Bruch’s membrane, MMPs, TIMPs, and MMPs polymorphisms in AMD. In both early and advanced AMD, the pathological dynamic changes of ECM structural components are caused by the dysfunction of specific regulators and by the influence of other regulatory systems connected with both genetic and environmental factors. Better insight into the pathological role of MMP/TIMP complexes may lead to the development of new strategies for AMD treatment and prevention.

HTRA1 rs11200638 variant and AMD risk from a comprehensive analysis about 15,316 subjects

BACKGROUND

The high-temperature requirement factor A1 (HTRA1) gene located at 10q26 locus has been associated with age-related macular degenerative (AMD), with the significantly related polymorphism being (rs11200638, -625G/A), however, above association is not consistent. We investigated a comprehensive analysis to evaluate the correlations between rs11200638 polymorphism and AMD susceptibility thoroughly addressing this issue.

METHODS

An identification was covered from the PubMed and Wanfang databases until 27th Jan, 2020. Odds ratios (OR) with 95% confidence intervals (CI) were applied to evaluate the associations. After a thorough and meticulous search, 35 different articles (33 case-control studies with HWE, 22 case-control studies about wet/dry AMD) were retrieved.

RESULTS

Individuals carrying A-allele or AA genotype may have an increased risk to be AMD disease. For example, there has a significantly increased relationship between rs11200638 polymorphism and AMD both for Asians (OR: 2.51, 95%CI: 2.22-2.83 for allelic contrast) and Caucasians [OR (95%CI) = 2.63(2.29-3.02) for allelic contrast]. Moreover, a similar trend in the source of control was detected. To classify the type of AMD, increased association was also observed in both wet (OR: 3.40, 95%CI: 2.90-3.99 for dominant model) and dry (OR: 2.08, 95%CI: 1.24-3.48 for dominant model) AMD. Finally, based on the different genotyping methods, increased relationships were identified by sequencing, TaqMan, PCR-RFLP and RT-PCR.

CONCLUSIONS

Our meta-analysis demonstrated that HTRA1 rs11200638 polymorphism may be related to the AMD development, especially about individuals carrying A-allele or AA genotype, who may be as identified targets to detect and intervene in advance. Further studies using Larger sample size studies, including information about gene-environment interactions will be necessary to carry out.

Haplotypes of HTRA1 rs1120638, TIMP3 rs9621532, VEGFA rs833068, CFI rs10033900, ERCC6 rs3793784, and KCTD10 rs56209061 Gene Polymorphisms in Age-Related Macular Degeneration

BACKGROUND

To determine the impact of HTRA1 rs1120638, TIMP3 rs9621532, VEGFA rs833068, CFI rs10033900, ERCC6 rs3793784, and KCTD10 rs56209061 genotypes on the development of age-related macular degeneration (AMD) in the Lithuanian population.

METHODS

A total of 916 subjects were examined: 309 patients with early AMD, 301 patients with exudative AMD, and 306 healthy controls. The genotyping of HTRA1 rs11200638, TIMP3 rs9621532, VEGFA rs833068, CFI rs10033900, ERCC6 rs3793784, and KCTD10 rs56209061 was carried out using the RT-PCR method.

RESULTS

Our study showed that single-nucleotide polymorphisms rs3793784 and rs11200638 were associated with increased odds of early and exudative AMD, and the variant in KCTD10 (rs56209061) was found to be associated with decreased odds of early and exudative AMD development after adjustments for age and gender in early AMD analysis and after adjustments only for age in exudative AMD. The haplotype containing two minor alleles C-A and the G-A haplotype in rs3793784-rs11200638 were statistically significantly associated with an increased risk of exudative AMD development after adjustment for age, while the G-G haplotype showed a protective role against early and exudative AMD and the haplotype C-G in rs3793784-rs11200638 was associated with a decreased risk only of exudative AMD development.

CONCLUSIONS

Our study identified two markers, rs11200638 and rs3793784, as risk factors for early and exudative AMD, and one marker, rs56209061, as a protective factor for early and exudative AMD development. The haplotypes constructed of rs3793784-rs11200638 were found to be associated with AMD development, as well.

CFH Y402H and VEGF Polymorphisms and Anti-VEGF Treatment Response in Exudative Age-Related Macular Degeneration

PURPOSE

The aim of this study was to evaluate the prevalence of single nucleotide polymorphisms (SNPs) in complement factor H (CFH) Y402H and VEGF rs2146323 and rs699947 in exudative age-related macular degeneration (AMD) and their relationship with intravitreal anti-VEGF treatment response.

METHODS

A total of 109 exudative AMD patients and 70 controls were included. Patients were classified as 'good responders' and 'nonresponders' based on the changes in best corrected visual acuity, central foveal thickness, lesion size, and the persistence of retinal hemorrhage after three dosages of anti-VEGF. We examined CFH, VEGF rs2146323 and rs699947 SNPs, and plasma interleukin-6 (IL-6) levels in both groups.

RESULTS

In total, 42 patients (38.5%) and 11 controls (15.7%) had homozygote wild genotype TT (p = 0.002). The variant C allele frequency was 45% in controls and 31.7% in patients (p = 0.011). A and C allele frequencies for VEGF rs699947 and rs2416323 were similar between the control and patient groups (p = 0.947, p = 0.378). Both SNPs were similar in responders and nonresponders. No significant difference was detected between plasma IL-6 levels of the control and AMD groups (p = 0.594), but the levels were higher in good responders than nonresponders (p < 0.001).

CONCLUSION

CFH Y402H SNP might be protective for AMD in the Turkish population. VEGF rs2146323 and rs699947 SNPs have no relationship to exudative AMD formation, and none of these seem to have any effect on anti-VEGF response.

The presence of CFH, HTRA1, ARMS2, VEGF-A and VEGF-R and the appearance of age-related macular degeneration sub-types

OBJECTIVE

To demonstrate the genetic influence in the onset of the different age-related macular disease (AMD) subtypes by analysing the genotype distribution of CFH, ARMS2, HTRA1, VEGF-A and VEGF-R polymorphisms in patients with neovascular and atrophic AMD.

MATERIALS AND METHODS

The study was conducted on 101 consecutive patients with AMD diagnosis (74 exudative, 27 atrophic) following Wisconsin international classification criteria. The CFH rs1410996, ARMS2 rs10940923, VEGF-A rs833061, rs699947, and VEGF-R rs2071559 polymorphisms were analysed using real time PCR with taqman probes, and HTRA1 rs112000638 using restriction endonucleases digestion. A study was made of the genotype distribution of the different polymorphisms in our group of patients with neovascular AMD and those with the atrophic type, and a comparison was made of the results for each one of the genes studied.

RESULTS

No statistically significant differences (P>.05) were found in the genotype distribution of the different polymorphisms between patients with neovascular AMD and patients with atrophic AMD in our population, although the "risk" genotypes tended to appear more frequently in patients with neovascular AMD, despite the lack of statistical significance.

CONCLUSIONS

Allelic variants of CFH, ARMS2, HTRA1, VEGF-A or VEGF-R genes are not associated with the different AMD subtypes. This suggests that, although the polymorphisms seem to be associated with the disease susceptibility, they are not involved in the onset of the different clinical variants of AMD. Further studies in different populations, and with a larger cohort of patients, are needed to confirm these results.

Current knowledge and trends in age-related macular degeneration: genetics, epidemiology, and prevention

PURPOSE

To address the most dynamic and current issues concerning human genetics, risk factors, pharmacoeconomics, and prevention regarding age-related macular degeneration.

METHODS

An online review of the database Pubmed and Ovid was performed, searching for the key words: age-related macular degeneration, AMD, pharmacoeconomics, risk factors, VEGF, prevention, genetics and their compound phrases. The search was limited to articles published since 1985 to date. All returned articles were carefully screened and their references were manually reviewed for additional relevant data. The webpage www.clinicaltrials.gov was also accessed in search of relevant research trials.

RESULTS

A total of 366 articles were reviewed, including 64 additional articles extracted from the references and 25 webpages and online databases from different institutions. At the end, only 244 references were included in this review.

CONCLUSION

Age-related macular degeneration is a complex multifactorial disease that has an uneven manifestation around the world but with one common denominator, it is increasing and spreading. The economic burden that this disease poses in developed nations will increase in the coming years. Effective preventive therapies need to be developed in the near future.

Genetic influences on the outcome of anti-vascular endothelial growth factor treatment in neovascular age-related macular degeneration

PURPOSE

To determine the association of genetic variants in known age-related macular degeneration (AMD) risk-associated genes with outcome of anti-vascular endothelial growth factor (VEGF) treatment in neovascular AMD.

DESIGN

Prospective cohort study.

PARTICIPANTS

We enrolled 224 consecutive patients with neovascular AMD at the Royal Victorian Eye and Ear Hospital, Australia.

METHODS

Patients were treated with 3 initial monthly ranibizumab or bevacizumab injections followed by 9 months of "as required" injections based on clinician's decision at each follow-up visit according to retreatment criteria. Seventeen single nucleotide polymorphisms (SNPs) in known AMD risk-associated genes including CFH (rs800292, rs3766404, rs1061170, rs2274700 and rs393955), HTRA1 (rs11200638), CFHR1-5 (rs10922153, rs16840639, rs6667243, and rs1853883), LOC387715/ARMS2 (rs3793917 and rs10490924), C3 (rs2230199 and rs1047286), C2 (rs547154), CFB (rs641153) and F13B (rs6003) were examined. Multivariate analysis was used to determine the role of each SNP in treatment outcome.

MAIN OUTCOME MEASURES

The influence of selected SNPs on mean change in visual acuity (VA) at 12 months.

RESULTS

Mean baseline VA was 51 ± 16.8 Early Treatment Diabetic Retinopathy Study letters. Overall, the mean change in VA from baseline was +3.2 ± 14.9 letters at 12 months. The AA (homozygote risk) genotype at rs11200638 - HTRA1 promoter SNP (P = 0.001) and GG (homozygote risk) genotype at rs10490924 (A69S) in LOC387715/ARMS2 (P = 0.002) were each significantly associated with poorer VA outcome at 12 months after multiple correction. Mean ± standard deviation change in VA from baseline in patients with AA genotype at rs11200638 was -2.9 ± 15.2 letters after 12 months compared with +5.1 ± 14.1 letters in patients with AG or GG genotypes at this SNP. Patients with either of these genotypes were also significantly more likely to lose >15 letters after 12 months. SNPs rs11200638 and rs10490924 were in high linkage disequilibrium (r(2) = 0.92). None of the other examined SNPs was associated with outcome.

CONCLUSIONS

The HTRA1 promoter SNP (rs11200638) and A69S at LOC387715/ARMS2 were associated with a poorer visual outcome for ranibizumab or bevacizumab treatment in neovascular AMD, suggesting strong pharmacogenetic associations with anti-VEGF treatment. This finding could aid in applying more individualized treatment regimens based on patients' genotype to achieve optimal treatment response in AMD.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Association between vascular endothelial growth factor +936 C/T gene polymorphism and age-related macular degeneration

Objectives

The pathogenesis of age-related macular degeneration (AMD) remains unknown. Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis and a target for inhibition therapy in wet AMD. This study investigated the association between the VEGF +936 C/T gene polymorphism and AMD, in a Chinese Han population.

Methods

Patients with AMD, and age- and sex-matched controls were enrolled. Restriction fragment length polymorphism was used to analyse the VEGF +936 polymorphism in the promoter and the 3′ untranslated region of the gene.

Results

The study included 200 AMD patients and 200 control subjects. There was a significantly higher prevalence of the TT genotype among AMD patients (9.0%) compared with controls (3.5%); the odds ratio for this genotype in AMD patients was 2.73 (95% confidence intervals 1.11, 6.68). There were no significant associations between any genotype and AMD subphenotypic categories (early, geographic atrophy, choroidal neovascularization).

Conclusions

The present study findings suggested that the VEGF +936 TT genotype was associated with AMD among Han Chinese patients.

Influence of CFH, HTRA1 and ARMS2 haplotype polymorphisms in the development of age-related macular disease

OBJECTIVE

To demonstrate genetic influence on the onset of age-related macular disease (AMD), analyzing genotype distribution of haplotypes, including polymorphisms of genes with proved relationships with AMD risk (CFH, ARMS2, HTRA1) in patients with AMD and in healthy people.

METHODS

We took 101 consecutive patients with an AMD diagnosis following Wisconsin international classification. For our control group, we took 91 patients without AMD or any significant macular changes. We analyzed CFH rs1410996, ARMS2rs 10940923 polymorphisms using real time PCR with taqman probes, and HTRA1 -625 using restriction endonuclease digestion. We studied haplotypes by simultaneously combining genotypes which, in previous studies, had been shown to have relationship with AMD (CFH, ARMS2, HTRA1) in patients with AMD and healthy people.

RESULTS

There was a statistically significant higher proportion of patients with AMD simultaneously expressing CFH GG (rs1410996) and ARMS2 TT (rs10940923) (P=.037; OR: 7.742 [1.010-63.156]); ARMS2 TT (rs10940923) and HTRA1-625 TT (P=.001; OR: 9.006 [2.019-40.168]) and CFH GG (rs1410996), ARMS2 TT (rs1040923) and HTRA1 -625 GG (P=.043; OR: 6.702 [1.003-55.565]) genotypes.

CONCLUSIONS

Haplotypes which combine "risk genotypes", demonstrated in previous studies, of our analyzed polymorphisms are more frequent in patients with AMD than in the control group, and they seem to increase the risk of suffering the disease in our population.

Genetic analysis of simultaneous geographic atrophy and choroidal neovascularization

AIM

To investigate clinical presentation and genotypes in patients with simultaneous geographic atrophy (GA) and choroidal neovascularization (CNV) and to compare with patients with GA or CNV only.

PATIENTS AND METHODS

Twenty patients with combined CNV-GA and 154 CNV only and 154 GA only were chosen based on clinical exam and imaging. Six single-nucleotide polymorphisms (SNPs)-rs2274700 and rs1061170 (complement factor H), rs10490924 and rs11200638 (HTRA1/LOC387715), rs2230199 (C3), rs9332739 (C2)-were genotyped using the SNaPshot method. Chi-squared tests were used for genetic analysis.

RESULTS

In patients with CNV-GA, GA progressed slowly and often preceded CNV. CNV presented as subretinal haemorrhage or fluid, with a sudden drop in visual acuity (VA). Comparing combined CNV-GA to GA and CNV only, patients with both had a higher frequency of at-risk alleles at both SNPs within the HTRA1 gene-rs10490924 (52.5%), rs11200638 (52.6%). Statistical significance was not achieved. CNV-GA patients had no protective alleles at SNP rs9332739 (C2), compared with GA (27%) and CNV only (10%).

CONCLUSION

There is a paucity of reports describing simultaneous CNV-GA. Clinical and genetic results may support the fact that GA and CNV fit on an age-related macular degeneration (AMD)-disease continuum and may clarify the disease processes in AMD.

Role of vascular endothelial growth factor polymorphisms in the treatment success in patients with wet age-related macular degeneration

PURPOSE

Along with environmental risk factors such as smoking, hypertension, and atherosclerosis, genetic susceptibility is a primary contributor to the development and progression of exudative age-related macular degeneration (AMD). Vascular endothelial growth factor (VEGF) is a central angiogenic regulator and there has been general agreement now that it is an important trigger for the progression of exudative AMD. In the present study, we tested the hypothesis that VEGF gene polymorphisms play a role in the treatment success with VEGF inhibitors in patients with exudative AMD.

DESIGN

Prospective cohort study.

PARTICIPANTS

We included 185 eyes of 141 patients with exudative AMD who were scheduled for their first treatment with intravitreally administered bevacizumab in this trial.

METHODS

All patients were aged >50 years and had angiographically verified exudative AMD. Blood from the finger pad was collected on blood cards for genotyping for the VEGF polymorphisms rs1413711, rs3025039, rs2010963, rs833061, rs699947, rs3024997, and rs1005230. At each follow-up visit, visual acuity was reassessed and an ophthalmic examination was carried out. Visual acuity outcome, number of retreatments, and overall time of treatment were analyzed in dependence of the VEGF polymorphisms.

MAIN OUTCOME MEASURES

Mean change in visual acuity at the end of the treatment period.

RESULTS

The included patients were reinjected with bevacizumab 1 to 15 times, resulting in a total treatment period of 42 to 1182 days. In univariate analysis only the G/G genotypes of rs3024997 and rs2010963 compared with all other 5 single nucleotide polymorphisms (SNPs) showed a significantly lower visual acuity at the end of treatment. In multivariate analysis including parameters such as time, baseline visual acuity, and number of reinjections, none of the SNPs showed a significant correlation.

CONCLUSIONS

The current study indicates that VEGF polymorphisms are not major predictors of anti-VEGF treatment success in patients with exudative AMD.

Complement activation as a biomarker for Alzheimer's disease

There is increasing evidence from genetic, immunohistochemical, proteomic and epidemiological studies as well as in model systems that complement activation has an important role in the pathogenesis of Alzheimer's disease (AD). The complement cascade is an essential element of the innate immune response. In the brain complement proteins are integral components of amyloid plaques and complement activation occurs at the earliest stage of the disease. The complement cascade has been implicated as a protective mechanism in the clearance of amyloid, and in a causal role through chronic activation of the inflammatory response. In this review we discuss the potential for complement activation to act as a biomarker for AD at several stages in the disease process. An accurate biomarker that has sufficient predictive, diagnostic and prognostic value would provide a significant opportunity to develop and test for effective novel therapies in the treatment of AD.

Age-related macular degeneration: genetic and environmental factors of disease

Age-related macular degeneration (AMD) is the most common cause of visual impairment among the elderly in developed countries, and its prevalence is thus increasing as the population ages; however, treatment options remain limited because the etiology and pathogenesis of AMD are incompletely defined. Recently, much progress has been made in gene discovery and mechanistic studies, which clearly indicate that AMD involves the interaction of multiple genetic and environmental factors. The identification of genes that have a substantial impact on the risk for AMD is not only facilitating the diagnosis and screening of populations at risk but is also elucidating key molecular pathways of pathogenesis. Pharmacogenetic studies of treatment responsiveness among patients with the "wet" form of AMD are increasingly proving to be clinically relevant; pharmacogenetic approaches hold great promise for both identifying patients with the best chance for vision recovery as well as tailoring individualized therapies.

Introduction to genetic epidemiology

Genetic epidemiology is of topical and increasingly practical relevance. The subject attempts to answer 2 questions: (1) is there a genetic component to a disease, and (2) what genes are involved? This article summarizes genetic epidemiologic methods, describing family- and population-based methods used to locate and identify genes and the advantages and disadvantages of each approach. Health care professionals are faced with more and more genetic information, both from interested patients and from the media, and understanding the principles underlying genetic studies allows such information to be placed in context.

Mediators of ocular angiogenesis

Angiogenesis is the formation of new blood vessels from pre-existing vasculature. Pathologic angiogenesis in the eye can lead to severe visual impairment. In our review, we discuss the roles of both pro-angiogenic and anti-angiogenic molecular players in corneal angiogenesis, proliferative diabetic retinopathy, exudative macular degeneration and retinopathy of prematurity, highlighting novel targets that have emerged over the past decade.

The molecular genetic basis of age-related macular degeneration: an overview

Age-related macular degeneration (AMD) is a complex disorder of the eye and the third leading cause of blindness worldwide. With a multifactorial etiology, AMD results in progressive loss of central vision affecting the macular region of the eye in elderly. While the prevalence is relatively higher in the Caucasian populations, it has gradually become a major public health issue among the non-Caucasian populations (including Indians) as well due to senescence, rapidly changing demographics and life-style factors. Recent genome-wide association studies (GWAS) on large case-control cohorts have helped in mapping genes in the complement cascade that are involved in the regulation of innate immunity with AMD susceptibility. Genes involved with mitochondrial oxidative stress and extracellular matrix regulation also play a role in AMD pathogenesis. Majority of the associations observed in complement (CFH, CFB, C2 and C3) and other (ARMS2 and HTRA1) genes have been replicated in diverse populations worldwide. Gene-gene (CFH with ARMS2 and HTRA1) interactions and correlations with environmental traits (smoking and body mass index) have been established as significant covariates in AMD pathology. In this review, we have provided an overview on the underlying molecular genetic mechanisms in AMD worldwide and highlight the AMD-associated-candidate genes and their potential role in disease pathogenesis.