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Biomedical subjects

Anthony P Khawaja

Publications and source records attributed to Anthony P Khawaja.

4 recordsLinked to original sources

Incidence patterns and genetic validation of primary glaucoma subtypes among 1 million adults in China and the UK.

BACKGROUND/AIMS: Primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) are distinct diseases, yet many glaucoma cases in population-based datasets lack subtype specification. We assessed incidence patterns of glaucoma subtypes in China and the UK and used genetic evidence to infer the likely subtype composition of cases recorded as unspecified glaucoma. METHODS: Incident primary glaucoma was identified from linked inpatient records in the prospective China Kadoorie Biobank (CKB; n=512 504) and UK Biobank (UKB; n=492 329) studies. Cohort-specific phenotyping algorithms defined POAG, PACG and unspecified glaucoma. Adjusted incidence rates were estimated by direct standardisation. To support subtype inference, polygenic risk scores (PRSs) were constructed using ancestry-specific genome-wide association studies, including a new East Asian PACG meta-analysis, and tested for association with glaucoma phenotypes using multivariable logistic regression. RESULTS: Over 12 years of follow-up, 1658 primary glaucoma cases were identified in CKB and 7643 in UKB. Most (>68%) cases lacked subtype specification. Incidence increased with age and was twofold higher among women for PACG in both cohorts and for unspecified glaucoma in CKB. In UKB, POAG incidence was fivefold higher among Black than White participants, with a similar but attenuated pattern for unspecified glaucoma. PRS analyses indicated that unspecified glaucoma closely aligned with PACG in CKB but was more heterogeneous in UKB. CONCLUSION: Healthcare-recorded incidence patterns for POAG and PACG were consistent with established demographic risk factors, whereas unspecified glaucoma showed differences in subtype composition between populations. Integrating epidemiological and genetic evidence improves interpretation of glaucoma phenotypes when detailed clinical information is unavailable.

Epidemiology↗

Decoding Primary Open-Angle Glaucoma: A Multi-Omics Approach to Identify Druggable Effector Genes.

PURPOSE: Genomewide association studies (GWAS) have identified numerous primary open angle glaucoma (POAG) risk loci, yet most reside in non-coding regions with unclear function. Mapping these loci to effector genes can elucidate disease mechanisms, identify functionally conserved variants, improve cross-ancestry risk prediction by reducing population-specific noise, and uncover shared therapeutic targets. METHODS: Here, we integrate European POAG GWAS with six types of multi-omics molecular Quantitative Trait Locis (xQTLs) using multi-trait colocalization to identify candidate effector variants and evaluate their cross-population relevance using genetic risk score (GRS) analysis, and their therapeutic potential through drug target prioritization. RESULTS: We identified 25 POAG effector variants colocalized with at least one xQTLs. In non-European populations, effector variants showed stronger effect size correlations with Europeans than non-colocalized variants (Pearson r2 = African 0.85 vs. 0.71; East Asian 0.81 vs. 0.69; and Latin American 0.91 vs. 0.75). Effector variants also had smaller allele frequency variations across populations (average interquartile range [IQR] = 0.15 vs. 0.20). The genetic risk score based on effector variants performed comparably to the genome-wide significant single-nucleotide polymorphism (SNP)-based GRS in non-European populations. Drug prioritization identified zinc, copper, sunitinib, probucol, and astemizole as potential common therapeutic agents for POAG and its subtypes. CONCLUSIONS: Our findings offer deeper insight into the molecular mechanisms underlying glaucoma and effector variants for developing more robust GRS models and broadly effective therapeutic strategies for POAG.

Humans↗

A Comprehensive Assessment of the Shared Genetic Architecture between Myopia and Open-Angle Glaucoma.

OBJECTIVE: Individuals with high myopia have an increased prevalence of open-angle glaucoma (OAG). We aim to clarify the possibly shared genetic architecture of myopia and OAG, in particular in high myopes with myopic macular degeneration (MMD), where OAG screening is highly challenging. DESIGN: Individual participant data meta-analysis of one-sample Mendelian randomization analyses and pleiotropic analysis under a composite null hypothesis. PARTICIPANTS: A total of 34 825 participants from 6 population-based cohort studies and 1 high myopia case-control study, including 708 OAG and 1953 high-myopia cases. METHODS: First, we calculated and validated genetic risk scores (GRSs) for OAG and myopia in each cohort. We subsequently meta-analyzed linear and logistic regression models for the association of a myopia GRS with OAG, intraocular pressure (IOP), and vertical cup-to-disc ratio (VCDR), and the association of an OAG-GRS with high myopia, axial length, and spherical equivalent. We stratified the analysis of OAG in different stages of axial elongation, and in high myopes with or without MMD. Pleiotropic analysis under a composite null hypothesis was applied to genome-wide association study summary statistics. MAIN OUTCOME MEASURES: Odds ratio (OR) of OAG and high myopia, and mean difference in IOP, VCDR, axial length, and spherical equivalent. RESULTS: One standard deviation (SD) increase in myopia GRS was associated with an OR (95% CI) of 1.18 (1.09, 1.28) for OAG, a beta (95% CI) of 0.04 (0.00, 0.08) mmHg in IOP, and of 0.005 (0.003, 0.007) in VCDR. The OAG-GRS was not significantly associated with high myopia compared to emmetropes, but a 1 SD increase was associated with a beta (95% CI) of 0.05 (0.01, 0.08) mm in axial length and of -0.05 (-0.10, -0.00) diopters in spherical equivalent. One SD increase in OAG-GRS had a substantially larger effect on OAG in high myopes with MMD, with an OR (95% CI) of 3.83 (1.89, 7.78) compared to 1.55 (1.24, 1.94) in emmetropes. Finally, we identified 95 independent pleiotropic single-nucleotide polymorphisms (SNPs). CONCLUSIONS: There is strong evidence for pleiotropy between myopia and OAG. Further research into the biological mechanisms of the identified pleiotropic SNPs is needed. An OAG-GRS might help to clinically estimate OAG risk, in particular in individuals with MMD. FINANCIAL DISCLOSURES: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Axial length↗

Genome-wide discovery reveals 30 loci for choroidal thickness and uncovers potential causal links with angle-closure glaucoma.

The choroid is critical for maintaining vision and implicated in several ocular diseases, being the sole source of nutrients and waste removal for the outer retina. Genetic discovery can help elucidate the pathways through which choroidal features influence disease risk. Our meta-analysis of genome-wide association studies (n= 78,682 participants) identified 30 genomic regions, including 20 novel loci, associated with choroidal thickness. Findings suggest inflammatory and vascular processes drive choroidal thickness, with overlapping mechanisms shared with refractive error. Genome-wide independently significant SNPs accounted for 18.7% of the genetic variance in choroidal thickness. Mendelian randomisation analyses showed a causal effect of age-related macular degeneration on choroidal thickness, and suggest a bidirectional causal effect between choroidal thickness and primary angle-closure glaucoma. These findings provide insight into the shared genetic architecture and biological pathways linking choroidal thickness and related diseases.

Canadian Longitudinal Study on Aging↗