Hypomethylation of the IL17RC Promoter in Peripheral Blood Leukocytes Is Not A Hallmark of Age-Related Macular Degeneration

• IL17RC is hypomethylated (<6%) in all peripheral blood samples examined
• IL17RC is not differentially methylated in three AMD cohorts
• IL17RC promoter shows hypomethylation in both mononuclear cells and granulocytes
• IL17RC hypomethylation in peripheral blood is not a suitable biomarker of AMD

SummaryAge-related macular degeneration (AMD) is a leading cause of visual impairment worldwide. Aberrant DNA methylation within the promoter of IL17RC in peripheral blood mononuclear cells has recently been reported in AMD. To validate this association, we examined DNA methylation of the IL17RC promoter in peripheral blood. First, we used Illumina Human Methylation450 Bead Arrays, a widely accepted platform for measuring global DNA methylation. Second, methylation status at multiple sites within the IL17RC promoter was determined by bisulfite pyrosequencing in two cohorts. Third, a methylation-sensitive quantitative PCR-based assay was performed on a subset of samples. In contrast to previous findings, we did not find evidence of differential methylation between AMD cases and age-matched controls. We conclude that hypomethylation within the IL17RC gene promoter in peripheral blood is not suitable for use as a clinical biomarker of AMD. This study highlights the need for considerable replication of epigenetic association studies prior to clinical application.

Graphical AbstractFigure optionsDownload as PowerPoint slide