Schematic diagrams of each gene highlighting region of methylation difference, the size of amplicon and the number and distribution of CpGs for each a) GRIK2 and b) BEGAIN, respectively. c) HRM results for GRIK2 show a decreased methylation in cases (Unpaired t test, p=0.025). d) Bs-cloning supports MDB-Seq and HRM results showing a cluster of the first 9 CpGs as significantly less methylated in cases (n=21, avg. 17 clones/sample) than controls (n=20, avg. 17 clones/sample) mixed model regression analysis was perform to assess significance of methylation at each CpG, *p<0.05, **p<0.01, ***p<0.001 exact values for pairwise comparison are in and cluster analysis in ). e) GRIK2 expression as measured by relative quantitation using TAQMAN probes shows an increasing in expression in cases (student t-test p= 0.012). f) GRIK2 expression correlates with the cluster of significantly differentially methylated CpGs (average methylation at each CpG, spearman r= −0.37, p=0.012). g) HRM results for BEGAIN show more methylation in cases compared to controls with (Unpaired t test with Welch’s correction, p=0.007). h) Bs-cloning for BEGAIN shows striking increase in methylation of cases (n=17, avg. 11 clones/sample) compared to controls (n=18, avg. 11 clones/sample) mixed model regression analysis was perform to assess significance of methylation at each CpG, *p<0.05, **p<0.01, #p<0.00, ϕ trend 0.053, exact values for pairwise comparison are in and cluster analysis in ). Cases showed on average a three-fold increase in methylation within cluster on BEGAIN. i) BEGAIN FAC sorted samples show a strong contribution of methylation from the non-neuronal cell fraction in case samples, whereas there is no difference in controls sample methylation between the two fractions (n=9 for all groups, avg. 17 clones/sample, one-way Anova F (3.32)=10.74, p<0.0001, Tukey’s pos-hoc, *p<0.05, ***p<0.001, ****p<0.0001). j) Analysis of BEGAIN variant expression in brain and blood. Experiment was independently repeated 3 times with 2 endogeneous controls per experiment, geometric mean of endogenous control was calculated and expression was normalized to this value. We qualitatively show that variant 1 is more expressed in brain and almost not present in blood, while we still detect variant 2 in blood. k) The astrocytic dyfunction group show a 2.3 fold decrease in the expression of BEGAIN Variant-1 compared to controls (Mann Whitney test p<0.0001), l) whereas variant-2 shows no change (Student t-test, p=0.26) m) The decrease in variant-1 expression correlates with the significantly differentially methylated cluster of CpGs in BEGAIN (average methylation at each CpG, spearman r=−0.37, p=0.019).