Research Paper Volume 8, Issue 7 pp 1485—1512

Figure 2. Epigenetic age acceleration in specific brain regions. Rows correspond to different brain regions. The first column (A,D,G,J,M,P) depicts DNAm age (y-axis) versus chronological age (x-axis) in different brain regions. The grey line corresponds to a spline regression model (based on 2 degrees of freedom) through non-HD samples. Epigenetic age acceleration was defined as the vertical distance of each sample from the spline regression line. The bar plots in the second column (B,E,H,K,N,Q) show the relationship between epigenetic age acceleration (y-axis) and HD status. The bar plots in the third column (C,F,I,L,O,R) involve the intrinsic measure of age acceleration that adjusts for the proportion of neurons. The rows correspond to samples from the parietal lobe, frontal lobe, occipital lobe, cingulate gyrus, motor cortex, and caudate nucleus. Each bar plot depicts the mean value and one standard error and reports a non-parametric group comparison test p-value (Kruskal Wallis Test). HD grade 4 samples were removed from this analysis.