Genomewide association study of epiretinal membrane: discovery of significant risk loci in each of three American populations

Abstract

IMPORTANCE: Epiretinal membrane (ERM) is a common retinal condition characterized by the presence of fibrocellular tissue on the retinal surface, often with consequent loss of vision and visual distortion. OBJECTIVE: Genomewide association studies (GWAS) can reveal the biology underlying complex genetic traits like ERM; there have been no previous large-scale GWAS of this trait. DESIGN: We used electronic health record diagnosis to identify Million Veteran Program (MVP) participants with ERM in three populations for genomewide association analysis and further statistical investigation of the results. SETTING: Veterans who volunteered for the nationwide Department of Veterans Affairs MVP study, eligible because they have used Veterans Health Administration facilities PARTICIPANTS: 31,374 European-American (EUR) cases and 414,052 EUR controls, 4,739 African-American (AFR) cases and 107,773 AFR controls, and 2,119 Latino (Admixed American, AMR) cases and 36,163 AMR controls, a total of 38,232 cases and 557,988 controls. METHODS: We completed GWAS in each population separately, then results were meta-analyzed. We also evaluated genetic correlation with other traits in external samples, and completed pathway enrichment analyses. MAIN OUTCOME MEASURES: Genomewide-significant association with ERM. RESULTS: Genomewide significant associations were observed in all three populations studied: 31 risk loci in EUR subjects, 3 in AFR, and 2 in AMR, with 48 identified in trans-ancestry meta-analysis. The most strongly associated locus in both EUR (rs9823832, p=9.06x10-37) and the meta-analysis (rs28630834, p=2.90x10-37) was DHX36 (DEAH-Box Helicase 36). We investigated expression quantitative trait locus associations for eye related function and found several GWS variants associate to alterations in gene expression in the macula, including DHX36*rs9438. ERM showed significant genetic correlation to depression and to disorders of the vitreous. Pathway enrichment analyses implicated collagen and collagen-adjacent mechanisms, among others. CONCLUSIONS AND RELEVANCE: This well-powered ERM GWAS has identified novel genetic associations, some very strong, that point to biological mechanisms for ERM and merit further investigation.