DNA methylation alterations in Lewy Body Dementia

Abstract Background The epigenetic mechanism of DNA methylation has been implicated in the pathophysiology of neurodegenerative disorders such as Lewy body dementia (LBD). DNA methylation profiling may help to identify novel treatment targets and early disease markers. We hypothesized that DNA methylation alterations are detectable in blood due the influence of genetic and environmental factors as well as immune system changes associated with LBD. Method Genome‐wide DNA methylation profiling was carried out using reduced representation bisulfite sequencing in blood samples from 89 LBD patients and 67 controls. Fifty five LBD patients had amyloid PET imaging. Data processing was performed using FastQC, TrimGalore, Bismark and MethylKit. DNA methylation alterations at specific CpG sites as well as at promoter, CpG island and CpG shore regions were compared between LBD cases and controls. A log odds logistic regression was used to identify differential DNA methylation after adjusting for age, sex and smoking status. The false discovery rate (FDR) was used for correction for multiple testing. We also tested the diagnostic classification performance of the differentially methylated regions using receiver operating characteristic (ROC) curve analysis and examined the potential of DNA methylation as a predictor of amyloid PET positivity in LBD. Result Two single CpG sites at TNFRSF1B and EMC6 and three CpG shore regions at ABCG5, ETAA1 and TENM4 reached genome‐wide significance in the differential DNA methylation analysis comparing LBD cases and controls. The combined panel of the top three differentially methylated CpG shores reached an area under the curve (AUC) of 0.91 for the diagnosis of LBD compared to controls (sensitivity 0.89, specificity 0.85). DNA methylation at TENM4 was associated with amyloid PET positivity in LBD with an AUC of 0.84 (sensitivity 0.99, specificity 0.55). Conclusion Our data suggest that DNA methylation alterations in blood are observed in a cohort of LBD patients compared to controls. Our findings need to be replicated in larger cohorts and tested for specificity in LBD in order to explore their future potential as diagnostic markers and/or targets for novel therapeutics.