Genome-Wide Meta-analysis Identifies Risk Loci and Improves Disease Prediction of Age-Related Macular Degeneration

Omega-3 Fatty Acids as Protective Factors for Age-Related Macular Degeneration: Prospective Cohort and Mendelian Randomization Analyses

PURPOSE

Epidemiologic studies and clinical trials have reported inconsistent findings regarding omega-3 fatty acids' protective role in age-related macular degeneration (AMD). We investigated their association in a prospective cohort and examined causality using Mendelian randomization (MR) analyses.

DESIGN

Prospective cohort study and 2-sample MR analyses.

PARTICIPANTS

The cohort included 258 350 AMD-free individuals of European descent from the UK Biobank. Mendelian randomization analyses used genome-wide association study data on plasma omega-3 and docosahexaenoic acid (DHA) (UK Biobank, n = 115 006) and AMD (dry, wet, and any; FinnGen, n = 208 690-209 122).

METHODS

Cox regression assessed the association between plasma omega-3 and DHA levels and AMD incidence, adjusting for systemic covariates and AMD polygenetic risk score (PRS). Interaction effects of AMD genetic risk (PRS, complement factor H and age-related maculopathy susceptibility 2 genotypes), and plasma omega-3 and DHA levels were tested. For MR analyses, we used random-effect inverse-variance weighted model as primary, with 5 sensitivity models. Causality was considered significant if P < 0.05 in the primary model and at least 2 sensitivity models.

MAIN OUTCOME MEASURES

Risk of AMD.

RESULTS

Over 12.9 years, 5068 people (1.9%) demonstrated AMD. Higher plasma levels (in millimoles per liter) of omega-3 (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.72-0.95; P = 0.006) and DHA (HR, 0.65; 95% CI, 0.44-0.96; P = 0.029) were associated with lower risk of receiving an AMD diagnosis. Mendelian randomization showed genetic predisposition to higher plasma omega-3 levels reduced the risk of dry AMD (odds ratio [OR], 0.83; 95% CI, 0.73-0.96; P = 0.010), wet AMD (OR, 0.76; 95% CI, 0.65-0.88; P < 0.001), and any AMD (OR, 0.82; 95% CI, 0.74-0.92; P < 0.001). Similar results were found for plasma DHA levels (wet AMD:OR, 0.79; 95% CI, 0.65-0.96; P = 0.017; any AMD: OR, 0.84; 95% CI, 0.72-0.98; P = 0.030). No significant interaction was found between omega-3 and DHA levels and AMD genetic risk (all P > 0.05).

CONCLUSIONS

Both the prospective and MR analyses suggest omega-3 and DHA may protect against AMD, supporting the need for further clinical trials to test their effectiveness in AMD prevention and treatment.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Artificial intelligence technology in ophthalmology public health: current applications and future directions

Global eye health has become a critical public health challenge, with the prevalence of blindness and visual impairment expected to rise significantly in the coming decades. Traditional ophthalmic public health systems face numerous obstacles, including the uneven distribution of medical resources, insufficient training for primary healthcare workers, and limited public awareness of eye health. Addressing these challenges requires urgent, innovative solutions. Artificial intelligence (AI) has demonstrated substantial potential in enhancing ophthalmic public health across various domains. AI offers significant improvements in ophthalmic data management, disease screening and monitoring, risk prediction and early warning systems, medical resource allocation, and health education and patient management. These advancements substantially improve the quality and efficiency of healthcare, particularly in preventing and treating prevalent eye conditions such as cataracts, diabetic retinopathy, glaucoma, and myopia. Additionally, telemedicine and mobile applications have expanded access to healthcare services and enhanced the capabilities of primary healthcare providers. However, there are challenges in integrating AI into ophthalmic public health. Key issues include interoperability with electronic health records (EHR), data security and privacy, data quality and bias, algorithm transparency, and ethical and regulatory frameworks. Heterogeneous data formats and the lack of standardized metadata hinder seamless integration, while privacy risks necessitate advanced techniques such as anonymization. Data biases, stemming from racial or geographic disparities, and the "black box" nature of AI models, limit reliability and clinical trust. Ethical issues, such as ensuring accountability for AI-driven decisions and balancing innovation with patient safety, further complicate implementation. The future of ophthalmic public health lies in overcoming these barriers to fully harness the potential of AI, ensuring that advancements in technology translate into tangible benefits for patients worldwide.

Leucine-Rich Repeat Kinase 2 Promotes Disintegration of Retinal Pigment Epithelial Cell: Implication in the Pathogenesis of Dry Age-Related Macular Degeneration

Recent epidemiologic studies have shown that patients with age-related macular degeneration (AMD) have a considerably higher risk of developing Parkinson disease (PD) later in life, suggesting a possible link between these diseases. However, the common mechanisms between these two diseases remain obscure, although the pathophysiology of each has been well investigated. In this study, we sought to explore the shared pathologic features of AMD and PD by focusing on leucine-rich repeat kinase 2 (LRRK2) and α-synuclein, both of which play crucial roles in PD pathogenesis. Immunohistochemistry for LRRK2 and α-synuclein was performed on human eye specimens. The effect of LRRK2 on retinal pigment epithelium (RPE) cell function was investigated using the RPE cell line hTERT-RPE1. Retinal morphology and function were examined in LRRK2-G2019S transgenic mice, representing mutants with increased kinase activity of LRRK2. Immunohistochemistry revealed that LRRK2 and α-synuclein were present in the RPE layer of the human eye. Overexpression of LRRK2 in RPE cells increased α-synuclein and induced cell death. LRRK2 inhibited α-synuclein degradation via phosphorylation of RAB GTPases. LRRK2-G2019S transgenic mice exhibited apoptosis of RPE and photoreceptors, choroidal thinning, and reduced electroretinogram amplitude, on top of α-synuclein protein accumulation in the RPE cell layer. Taken together, the current study revealed that LRRK2 is one of the key molecules involved in the common pathologic mechanisms of AMD and PD.

Genome-wide association studies, Polygenic Risk Scores and Mendelian randomisation: an overview of common genetic epidemiology methods for ophthalmic clinicians

Genetic information will be increasingly integrated into clinical eye care within the current generation of ophthalmologists. For monogenic diseases such as retinoblastoma, genetic studies have been relatively straightforward as these conditions result from pathogenic variants in a single gene resulting in large physiological effects. However, most eye diseases result from the cumulative effects of multiple genetic variants and environmental factors. In such diseases, because each variant usually has an individually small effect, genetic studies for complex diseases are comparatively more challenging. This article aims to provide an overview of three genetic epidemiology methods for polygenic (or complex) diseases: genome-wide association studies (GWAS), Polygenic Risk Scores (PRS) and Mendelian randomisation (MR). A GWAS systematically conducts association analyses of a trait of interest against millions of genetic variants, usually in the form of single nucleotide polymorphisms, across the genome. GWAS findings can then be used for PRS construction and MR analyses. To construct a PRS, the cumulative effect of many genetic variants associated with a trait from a prior GWAS is calculated and taken as a quantitative representation of an individual's genetic risk of a complex disease. MR studies analyse an outcome measure against the genetic variants of an exposure, and are particularly useful in investigating causal relations between two traits where randomised controlled trials are not possible or ethical. In addition to explaining the principles of these three genetic epidemiology concepts, this article provides a minimally technical description of their basic methodology that is accessible to the non-expert reader.

A cross-tissue transcriptome-wide association study identified susceptibility genes for age-related macular degeneration

Age-related macular degeneration (AMD) is a complex multifactorial disease with a significant genetic component. Despite extensive research efforts, the underlying molecular mechanisms remain elusive, necessitating innovative approaches to identify specific genes involved in the pathogenesis of AMD and to elucidate their functional mechanisms. A transcriptome-wide association study (TWAS) was conducted by integrating eQTL data from 49 tissues of the Genotype-Tissue Expression Project (GTEx) v8 and AMD data from FinnGen R10. The Unified Test for Molecular Signatures (UTMOST) and Functional Summary-based Imputation (FUSION) were used to evaluate gene associations with AMD across tissues and within individual tissues, respectively. Multi-marker Analysis of Genomic Annotation (MAGMA) was employed to validate results and identify reliable susceptibility genes, followed by summary data-based Mendelian randomization (SMR) and colocalization analyses to explore causal associations. The cross-tissue and single-tissue TWAS analyses identified 12 reliable AMD-associated genes. MAGMA analysis confirmed 6 of these as reliable susceptibility genes. SMR analysis provided further validation of these genes, although colocalization results were not significant. This study identified six susceptibility genes associated with the risk of AMD through a cross-tissue TWAS, providing new insights into the potential systemic regulatory mechanisms underlying AMD.

Investigating the Link between Psychological Well-Being and Early-Stage Age-Related Macular Degeneration: A Mendelian Randomization Analysis

PURPOSE

While some studies have started to focus on the link between psychological well-being and age-related macular degeneration (AMD), the relationship remains uncertain. Our research aims to provide new insights into this association, laying a foundation for future interventions and addressing existing knowledge gaps.

METHODS

We utilized the "TwoSampleMR" package in R for a bidirectional Mendelian randomization analysis of psychological well-being (subjective well-being, depression, neuroticism, and Sensitivity to Environmental Stress and Adversity) and early-stage AMD. Causal effects were estimated using the inverse-variance weighted method, and additional methods included weighted median and MR-Egger regression. Sensitivity analyses included Cochran's Q test, MR-Egger intercept analysis, MR-PRESSO, and leave-one-out analysis.

RESULTS

The study found that the population with genetic predisposition to neuroticism had a 39.7% lower risk of early-stage AMD (OR = 0.603, 95% CI = 0.385-0.945, p = 0.027). Conversely, the population with genetic predisposition to subjective well-being had a 3.2% increased risk of early-stage AMD (OR = 1.032, 95% CI = 1.003-1.063, p = 0.029). No significant causal relationships were found from depression or Sensitivity to Environmental Stress and Adversity to early-stage AMD, nor from early-stage AMD to psychological well-being.

CONCLUSION

This study provides preliminary evidence that the relationship between psychological well-being and early-stage AMD may be complex and multifaceted. It suggests that moderate neuroticism levels might reduce early-stage AMD risk through health behaviors, pathophysiological mechanisms, and other factors, while high subjective well-being levels might increase this risk similarly. However, these findings are insufficient for preventive strategies due to a lack of substantial evidence and still require extensive experimental research for further validation.

Systematic dissection of pleiotropic loci and critical regulons in excitatory neurons and microglia relevant to neuropsychiatric and ocular diseases

Advancements in single-cell multimodal techniques have greatly enhanced our understanding of disease-relevant loci identified through genome-wide association studies (GWASs). To investigate the biological connections between the eye and brain, we integrated bulk and single-cell multiomic profiles with GWAS summary statistics for eight neuropsychiatric and five ocular diseases. Our analysis uncovered five latent factors explaining 61.7% of the genetic variance across these 13 diseases, revealing diverse correlational patterns among them. We identified 45 pleiotropic loci with 91 candidate genes that contribute to disease risk. By integrating GWAS and single-cell profiles, we implicated excitatory neurons and microglia as key contributors in the eye-brain connections. Polygenic enrichment analysis further identified 15 pleiotropic regulons in excitatory neurons and 16 in microglia that were linked to comorbid conditions. Functionally, excitatory neuron-specific regulons were involved in axon guidance and synaptic activity, while microglia-specific regulons were associated with immune response and cell activation. In sum, these findings underscore the genetic link between psychiatric disorders and ocular diseases.

Neuroretinal and RPE changes and susceptibility to Age-Related Macular Degeneration: insights from the longitudinal Alienor Study

PURPOSE

We assessed the associations of macular layer thicknesses, measured using spectral-domain OCT (SD-OCT), with incident age-related macular degeneration (AMD) and AMD polygenic risk scores (PRS).

DESIGN

Population-based cohort study PARTICIPANTS: 653 participants of the Alienor study, with biennial eye imaging from 2009 to 2024.

METHODS

Macular layer thicknesses of eight distinct layers and three compound layers were automatically segmented based on SD-OCT imaging of the macula. Total and pathway specific PRS were calculated from previous AMD genome-wide association studies summary statistics. Associations of macular layer thicknesses with incident intermediate and advanced AMD were analyzed using time-dependent Cox proportional hazards models. Associations of macular layer thicknesses with PRS were assessed using linear mixed models.

MAIN OUTCOME MEASURES

Incident intermediate and advanced AMD based on fundus colour photographs and SD-OCT.

RESULTS

Mean age at first OCT examination of the 653 participants was 82.2 ± 4.2 years and 61.3 % were women. In multivariate adjusted models, incident intermediate AMD was associated with thicker retinal pigment epithelium (RPE) - Bruch's Membrane (BM) complex in the 1 mm central circle (Hazard ratio (HR)= 1.13 for 1 μm increase; PFDR= 8.08 x 10-4). Incident advanced AMD was associated with thicker RPE-BM complex in both the central circle (HR= 1.09; PFDR= 0.005) and the inner circle (1 mm - 3 mm) (HR= 1.28; PFDR= 1.61 x 10-5). Over the study period, RPE-BM complex thickening in the inner circle was more pronounced in individuals with high total PRS (ß= 0.06 μm/year for 1 standard deviation increase, PFDR= 1.61 x 10-10), high complement pathway PRS (ß= 0.04 μm/year, PFDR=3.23 x 10-5), high lipid pathway PRS (ß= 0.03 μm/year, PFDR= 3.74 x 10-4) and ARMS2 (ß= 0.03 μm/year, PFDR= 0.002). Further, high total PRS and high complement-specific PRS were associated with thinner photoreceptor segment layer (PSL) at baseline and with thinning of the outer nuclear layer over the study period.

CONCLUSION

These results highlight the importance of RPE-BM complex thickening in the pathophysiological sequence of AMD. Further longitudinal studies are needed, in particular to determine the value of RPE-BM thickening and PSL thinning measured using SD-OCT for the clinical follow-up of AMD patients.

High-Density Lipoproteins Associate with Age-Related Macular Degeneration in the All of Us Research Program

PURPOSE

Extracellular lipoprotein aggregation is a critical event in age-related macular degeneration (AMD) pathogenesis. In this study, we sought to analyze associations between clinical and genetic-based factors related to lipoprotein metabolism and risk for AMD in the All of Us research program.

DESIGN

Cross-sectional retrospective data analysis.

PARTICIPANTS

A total of 5028 healthy participants and 2328 patients with AMD from All of Us.

METHODS

Participants with and without AMD were age, race, and sex matched in a 1:2 ratio, respectively. Smoking status, history of hyperlipidemia, and statin use were extracted in a binary manner. Statin use was further subcategorized into hepatically versus nonhepatically metabolized statins. Laboratory values for low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TGs) were also extracted, and outliers were excluded from analysis. The PLINK toolkit was used to extract single nucleotide polymorphisms (SNPs) associated with LDL and HDL dysregulation, as published in prior work. Odds ratio curves were computed to assess the risk between LDL, TG, and HDL versus AMD. All clinical and genetic variables were input into a multivariable logistic regression model, and odds ratios and P values were generated.

MAIN OUTCOME MEASURES

Statistical significance of risk factors for AMD, thresholded at P ≤ 0.05.

RESULTS

On multivariable regression analysis, statin use and low and high HDL were significantly associated with increased AMD risk (P < 0.001 for all variables). Additionally, the multivariable regression implicated HDL-associated SNP's increased risk for AMD. Last, LPA was identified (P = 0.007) as a novel SNP associated with increased AMD risk.

CONCLUSIONS

There exists a U-shaped relationship between HDL and AMD risk, such that high and low HDL are significantly associated with increased AMD risk. Additionally, SNPs associated with HDL metabolism are associated with AMD risk. This analysis further establishes the role of HDL in AMD pathogenesis.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Physiology and pathophysiology of the retinal neuroglia

Neuroglia of the retina are represented by Müller glia, parenchymal astrocytes, microglia and oligodendrocytes mainly associated with the optic nerve. Müller glia are the most numerous glia, endowed with multiple homeostatic functions and indispensable for the retinal morphofunctional organization. Müller cells integrate retinal neurons into individual functional units (known as retinal columns) and act as a living light guide, transmitting photons to photoreceptors. In pathology, retinal neuroglia undergo complex changes, which include upregulation of neuroprotection, reactive gliosis, and functional asthenia. The balance between all these changes defines the progression and outcome of retinal disorders.

Nocturnal hypoxia and age-related macular degeneration

BACKGROUND

Nocturnal hypoxia is common, under-diagnosed and is found in the same demographic at risk of age-related macular degeneration (AMD). The objective of this study was to determine any association between nocturnal hypoxia and AMD, its severity, and the high-risk sub-phenotype of reticular pseudodrusen (RPD).

METHODS

This cross-sectional study included participants aged ≥50 years with AMD, or normal controls, exclusive of those on treatment for obstructive sleep apnoea. All participants had at home, overnight (up to 3 nights) pulse oximetry recordings and multimodal imaging to classify AMD. Classification of Obstructive Sleep Apnea (OSA) was determined based on oxygen desaturation index [ODI] with mild having values of 5-15 and moderate-to-severe >15.

RESULTS

A total of 225 participants were included with 76% having AMD, of which 42% had coexistent RPD. Of the AMD participants, 53% had early/intermediate AMD, 30% had geographic atrophy (GA) and 17% had neovascular AMD (nAMD). Overall, mild or moderate-to-severe OSAwas not associated with an increased odds of having AMD nor AMD with RPD (p ≥ 0.180). However, moderate-to-severe OSA was associated with increased odds of having nAMD (odds ratio = 6.35; 95% confidence interval = 1.18 to 34.28; p = 0.032), but not early/intermediate AMD or GA, compared to controls (p ≥ 0.130). Mild OSA was not associated with differences in odds of having AMD of any severity (p ≥ 0.277).

CONCLUSIONS

There was an association between nocturnal hypoxia as measured by the ODI and nAMD. Hence, nocturnal hypoxia may be an under-appreciated important modifiable risk factor for nAMD.

Loss of CFHR5 function reduces the risk for age-related macular degeneration

Age-related macular degeneration (AMD) is a prevalent cause of vision loss in the elderly with limited therapeutic options. A single chromosomal region around the complement factor H gene (CFH) is reported to explain nearly 25% of genetic AMD risk. Here, we used association testing, statistical finemapping and conditional analyses in 12,495 AMD cases and 461,686 controls to deconvolute four major CFH haplotypes that convey protection from AMD. We show that beyond CFH, two of these are explained by Finn-enriched frameshift and missense variants in the CFH modulator CFHR5. We demonstrate through a FinnGen sample recall study that CFHR5 variant carriers exhibit dose-dependent reductions in serum levels of the CFHR5 gene product FHR-5 and two functionally related proteins at the locus. Genetic reduction in FHR-5 correlates with higher preserved activities of the classical and alternative complement pathways. Our results propose therapeutic downregulation of FHR-5 as promising to prevent or treat AMD.

Machine learning model for age-related macular degeneration based on heavy metals: The National Health and Nutrition Examination Survey 2005 to 2008

Age-related macular degeneration (AMD) is the leading cause of blindness in older people in developed countries. It has been suggested that heavy metal exposure may be associated with the development of AMD, but most studies have focused on the effects of a single metal with traditional methods. In this study, we analyzed the relationship between 13 urinary heavy metal concentrations and AMD using NHANES data between 2005 and 2008. We constructed and compared 11 machine learning models to identify the best model for predicting AMD risk. We further interpreted the models by Permutation Feature Importance (PFI), Partial Dependence Plot (PDP) analysis, and SHapley Additive exPlanations (SHAP) analysis. 216 AMD patients out of 2380 participants. The random forest (RF) model performed optimally in predicting the risk of AMD, with an AUC value of 0.970. PFI analyses revealed that age and urinary cadmium (Cd) were the main factors influencing the risk of AMD. SHAP analyses further confirmed the significance of Cd concentration in predicting the risk of AMD, and we revealed a significant interaction with significant interaction of race. Our study firstly explored the relationship between heavy metal exposure levels and AMD based on machine learning techniques, found that urinary Cd concentration had the greatest impact on AMD, and revealed the superior predictive performance of machine learning methods. Furthermore, our study provided a new perspective for early screening and intervention of AMD.

Adult Onset Foveomacular Vitelliform Dystrophy Shows Genetic Overlap With Age-Related Macular Degeneration

Purpose

Adult-onset foveomacular vitelliform dystrophy (AFVD) shares phenotypic similarities with age-related macular degeneration (AMD). The genetic factors associated with AFVD are unknown in >80% of cases. This study evaluated the association of known AMD genetic risk variants with AFVD and compared systemic complement activation in these conditions.

Methods

Clinical, imaging, and genetic data were collected from 50 patients with AFVD (men/women = 25/25, mean age ± SD 73 ± 10 years), 917 patients with AMD (men/women = 377/540, mean age ± SD 77 ± 9 years), and 432 unaffected healthy controls (men/women = 202/230, mean age ± SD 71 ± 8 years). Genotyping focused on 52 single nucleotide polymorphisms (SNPs) linked to AMD. Weighted genetic risk scores (GRS) for 19 complement system associated variants, 7 lipid metabolism associated variants, the remaining 26 variants (other pathways GRS), and for all 52 variants (global score) were derived and correlated with phenotype.

Results

Of the 52 SNPs evaluated, CFH (rs570618) and C2/CFB/SKIV2L (rs116503776 and rs114254831) were associated with AFVD compared with healthy controls (odds ratio [OR] = 2.73, 95% confidence interval [CI] = 1.32-5.73, P = 0.01; OR = 0.31, 95% CI = 0.14-0.71, P = 0.0036; and OR = 0.41, 95% CI = 0.22-0.74, P = 0.0025, respectively). MIR6130/RORB (rs10781182) was negatively associated with AFVD compared with the healthy controls (OR = 0.13, CI = 0.06-0.25, P < 0.0001) and AMD (OR = 0.19, CI = 0.10-0.34, P < 0.0001). Regression analysis showed complement GRS was positively associated with AFVD compared with controls (OR = 1.42, 95% CI = 1.04-1.95, P = 0.03), whereas the other pathways' GRS was negatively associated (OR = 0.46, 95% CI = 0.21-0.98, P = 0.04). AMD was positively associated with the complement score, global score, and ARMS2/HTRA1 compared with controls.

Conclusions

Non-monogenic AFVD is associated with AMD risk alleles in the complement cascade, but not in other pathways. Further research is needed to explore complement inhibition for AFVD.

Aberrant Lipid Metabolism and Complement Activation in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) stands as a leading cause of severe visual impairment and blindness among the elderly globally. As a multifactorial disease, AMD's pathogenesis is influenced by genetic, environmental, and age-related factors, with lipid metabolism abnormalities and complement system dysregulation playing critical roles. This review delves into recent advancements in understanding the intricate interaction between these two crucial pathways, highlighting their contribution to the disease's progression through chronic inflammation, drusen formation, and retinal pigment epithelium dysfunction. Importantly, emerging evidence points to dysregulated lipid profiles, particularly alterations in high-density lipoprotein levels, oxidized lipid deposits, and intracellular lipofuscin accumulation, as exacerbating factors that enhance complement activation and subsequently amplify tissue damage in AMD. Furthermore, genetic studies have revealed significant associations between AMD and specific genes involved in lipid transport and complement regulation, shedding light on disease susceptibility and underlying mechanisms. The review further explores the clinical implications of these findings, advocating for a novel therapeutic approach that integrates lipid metabolism modulators with complement inhibitors. By concurrently targeting these pathways, the dual-targeted approach holds promise in significantly improving outcomes for AMD patients, heralding a new horizon in AMD management and treatment.

Comprehensive Evaluation of the Genetic Basis of Keratoconus: New Perspectives for Clinical Translation

Purpose

Keratoconus (KC) is a corneal disorder with complex etiology, apparently involving both genetic and environmental factors, characterized by progressive thinning and protrusion of the cornea. We aimed to identify novel genetic regions associated with KC susceptibility, elucidate relevant genes for disease development, and explore the translational implications for therapeutic intervention and risk assessment.

Methods

We conducted a genome-wide association study (GWAS) that integrated previously published data with newly generated genotyping data from an independent European cohort. To evaluate the clinical translation of our results, we performed functional annotation, gene prioritization, polygenic risk score (PRS), and drug repositioning analyses.

Results

We identified two novel genetic loci associated with KC, with rs2806689 and rs807037 emerging as lead variants (P = 1.71E-08, odds ratio [OR] = 0.88; P = 1.93E-08, OR = 1.16, respectively). Most importantly, we identified 315 candidate genes influenced by confirmed KC-associated variants. Among these, MINK1 was found to play a pivotal role in KC pathogenesis through the WNT signaling pathway. Moreover, we developed a PRS model that successfully differentiated KC patients from controls (P = 7.61E-16; area under the curve = 0.713). This model has the potential to identify individuals at high risk for developing KC, which could be instrumental in early diagnosis and management. Additionally, our drug repositioning analysis identified acetylcysteine as a potential treatment option for KC, opening up new avenues for therapeutic intervention.

Conclusions

Our study provides valuable insights into the genetic and molecular basis of KC, offering new targets for therapy and highlighting the clinical utility of PRS models in predicting disease risk.

Genetic Risk of Reticular Pseudodrusen in Age-Related Macular Degeneration: HTRA1 /lncRNA BX842242.1 dominates, with no evidence for Complement Cascade involvement

Age-related macular degeneration (AMD) is a multifactorial retinal disease with a large genetic risk contribution. Reticular pseudodrusen (RPD) is a sub-phenotype of AMD with a high risk of progression to late vision threatening AMD. In a genome-wide association study of 2,165 AMD+/RPD+ and 4,181 AMD+/RPD-compared to 7,660 control participants, both chromosomes 1 ( CFH ) and 10 ( ARMS2/HTRA1 ) major AMD risk loci were reidentified. However association was only detected for the chromosome 10 locus when comparing AMD+/RPD+ to AMD+/RPD-cases. The chromosome 1 locus was notably absent. The chromosome 10 RPD risk region contains a long non-coding RNA (ENSG00000285955/BX842242.1) which colocalizes with genetic markers of retinal thickness. BX842242.1 has a strong retinal eQTL signal, pinpointing the parafoveal photoreceptor outer segment layer. Whole genome sequencing of phenotypically extreme RPD cases identified even stronger enrichment for the chromosome 10 risk genotype.

Fundus Image Deep Learning Study to Explore the Association of Retinal Morphology with Age-Related Macular Degeneration Polygenic Risk Score

BACKGROUND

Age-related macular degeneration (AMD) is a complex eye disorder with an environmental and genetic origin, affecting millions worldwide. The study aims to explore the association between retinal morphology and the polygenic risk score (PRS) for AMD using fundus images and deep learning techniques.

METHODS

The study used and pre-processed 23,654 fundus images from 332 subjects (235 patients with AMD and 97 controls), ultimately selecting 558 high-quality images for analysis. The fine-tuned DenseNet121 deep learning model was employed to estimate PRS from single fundus images. After training, deep features were extracted, fused, and used in machine learning regression models to estimate PRS for each subject. The Grad-CAM technique was applied to examine the relationship between areas of increased model activity and the retina's morphological features specific to AMD.

RESULTS

Using the hybrid approach improved the results obtained by DenseNet121 in 5-fold cross-validation. The final evaluation metrics for all predictions from the best model from each fold are MAE = 0.74, MSE = 0.85, RMSE = 0.92, R2 = 0.18, MAPE = 2.41. Grad-CAM heatmap evaluation showed that the model decisions rely on lesion area, focusing mostly on the presence of drusen. The proposed approach was also shown to be sensitive to artifacts present in the image.

CONCLUSIONS

The findings indicate an association between fundus images and AMD PRS, suggesting that deep learning models may effectively estimate genetic risk for AMD from retinal images, potentially aiding in early detection and personalized treatment strategies.

Polygenic Risk Scores and Genetically Complex Eye Disease

The success of genome-wide association studies (GWASs) in uncovering genetic variants associated with complex eye diseases has paved the way for the development of risk prediction approaches based on disease genetics. Derived from GWAS data, polygenic risk scores (PRSs) have been emerging as a promising indicator of an individual's genetic liability to disease. In this review, we recap the current progress of PRS development and utility across a range of common eye diseases. While illustrating the prediction accuracy of PRSs and their valuable role in risk stratification for certain eye diseases, we also address PRSs' uncertain implementation in clinical settings at this stage, particularly in circumstances where limited treatment options are available. Finally, we discuss obstacles in translating PRSs into practice, including barriers to clinical impact, issues when working with different ancestry groups, and communicating risk scores, as well as projections for future improvements.

Ocular Pharmacology

Treatment of ocular diseases presents unique challenges and opportunities for the clinician and for the clinical pharmacologist. Ophthalmic pharmaceuticals, typically given as liquids, require consideration of solubility, physiological pH, and osmolarity, as well as sterility and stability, which in turn requires optimal pharmaceutics. Ocular tissue levels are challenging to obtain in humans, and the clinical pharmacokinetics is typically blood levels, which are primarily related to safety, rather than efficacy. The eye is a closed compartment with multiple physiological barriers with esterases and transporters, but relatively little cytochrome oxidases. Delivery routes include topical, intravitreal, and systemic. Patient dosing involves not only adherence issues common to all chronic diseases, but also performance requirements on eye drop instillation. Therapeutically, ocular diseases and their pharmacological treatments include both those analogous to systemic diseases (e.g., inflammation, infection, and neuronal degeneration) and those unique to the eye (e.g., cataract and myopia).

Age-related macular degeneration discordance in monozygotic twin pairs

PURPOSE

To examine age-related macular degeneration (AMD) and retinal pigment epithelium (RPE)-Bruch's membrane (BrM) complex volume associations in monozygotic twin pairs.

METHODS

In this study, 106 elderly twins (53 twin pairs) from the Finnish Twin Cohort study were recruited. Each participant underwent dilated 35-degree digital colour fundus photography (CFP), and spectral domain optical coherence tomography (OCT) and replied to a structured study questionnaire. The CFPs were graded according to the Age-Related Eye Disease Study (AREDS) classification. The OCT images were segmented and volumetric data of the RPE-BrM complex volume was calculated with the Orion™ software. The worse eye according to AREDS classification was used for the analysis.

RESULTS

Twenty-nine (55%) of the twin pairs were discordant with regard to AREDS classification. Fourteen (26%) pairs were discordant with one twin participant having AMD (AREDS 2-4) and the other being unaffected (AREDS 1). Four (8%) pairs had one twin participant with intermediate or late AMD (AREDS 3-4) versus the other being unaffected (AREDS 1). The within-pair polychoric correlation for AREDS was 0.605 (95% confidence interval 0.418-0.792). In multivariate analysis intermediate and late AMD as well as age associated with RPE-BrM complex volume. RPE-BrM complex volume showed a within twin pair correlation, r = 0.430 (95% confidence interval 0.172-0.688, p < 0.01).

CONCLUSION

A substantial proportion of monozygotic twin pairs are discordant with regard to age-related macular degeneration phenotype. RPE-BrM complex volume associated with age and intermediate and late AMD.

Predictive Performance of an Updated Polygenic Risk Score for Age-Related Macular Degeneration

PURPOSE

A recent genome-wide association study of age-related macular degeneration (AMD) identified new AMD-associated risk variants. These variants now can be incorporated into an updated polygenic risk score (PRS). This study aimed to assess the performance of an updated PRS, PRS2023, in an independent cohort of older individuals with retinal imaging data and to compare performance with an older PRS, PRS2016.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 4175 participants of European ancestry, 70 years of age or older, with genotype and retinal imaging data.

METHODS

We used logistic regression models and area under the receiver operating characteristic curve (AUC) to assess the performance of PRS2023 compared with PRS2016. AMD status and severity were graded using color fundus photography.

MAIN OUTCOME MEASURES

Association of PRS2023 and PRS2016 with AMD risk at baseline.

RESULTS

At enrollment among 4175 participants, 2605 participants (62.4%) had no AMD and 853 participants (20.4%), 671 participants (16.1%), and 46 participants (1.1%) had early, intermediate, and late-stage AMD, respectively. More than 27% of the participants with a high PRS2023 (top quartile) had intermediate or late-stage AMD, compared with < 15% for those in the middle 2 quartiles and less than 13% for those in the lowest quartile. Both PRS2023 and PRS2016 were associated significantly with AMD after adjustment for age, sex, smoking status, and lipid levels, with increasing odds ratios (ORs) for worsening AMD grades. PRS2023 outperformed PRS2016 (P = 0.03 for all AMD and P = 0.03 for late AMD, DeLong test comparing AUC). PRS2023 was associated with late-stage AMD with an adjusted OR of 5.05 (95% confidence interval [CI], 3.41-7.47) per standard deviation. The AUC of a model containing conventional or nongenetic risk factors and PRS2023 was 91% (95% CI, 87%-95%) for predicting late-stage AMD, which improved 12% over the model without the PRS (AUC, 79%; P < 0.001 for difference).

CONCLUSIONS

A new PRS, PRS2023, for AMD outperforms a previous PRS and predicts increasing risk for late-stage AMD (with stronger association for more severe imaging-confirmed AMD grades). Our findings have clinical implications for the improved prediction and risk stratification of AMD.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.