Age related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly population worldwide. While recent studies have demonstrated strong genetic associations of single nucleotide polymorphisms within a number of genes and AMD, other modes of regulation are also likely to play a role in its aetiology. We undertook DNA methylation microarray analysis on monozygotic and dizygotic twins who were discordant for AMD and identified methylated IL17RC promoters as being present only in non-AMD control individuals rather than in AMD patients. We validated this finding of a significantly decreased level of methylation on the IL17RC promoter in AMD siblings as well as in a case control study involving 202 genetically unrelated AMD patients and 96 controls (95% CI, 0.03-0.17, P=3.1x10-8). Further, we showed that hypomethylation of the IL17RC promoter in AMD patients led to an elevated expression of its protein and mRNA in peripheral blood as well as in the retina and choroid, suggesting that the DNA methylation pattern and expression of IL17RC may potentially serve as a biomarker for the diagnosis of AMD and likely plays a role in disease pathogenesis.