Fig. 5.

Long PD disease course is associated with high levels of hemispheric asymmetry in DNA methylation. Significant DNA methylation changes associated with PD duration were identified (n = 2910 cytosine sites, q < 0.05, robust linear regression with contrasts, controlling for age, sex, postmortem interval, neuronal subtype proportion, and brain hemisphere side). The extent of hemispheric asymmetry for cytosine sites associated with PD duration was determined in PD patients with a short (≤ 15 years) or long (> 15 years) disease course (n = 14 and 12 individuals, respectively). a The extent of hemispheric asymmetry in DNA methylation in PD patients with a short or long disease course. The boxplot center line is the median, the lower and upper limits are the first and third quartiles (25th and 75th percentiles), and the whiskers are 1.5 × the interquartile range. p < 0.001 is the difference between the short and long disease course groups in level of DNA methylation asymmetry, as determined by t-test. b Pathways differing between PD patients with a short or long disease course. Pathway enrichment analysis of genes with epigenetic differences associated with PD duration was performed by g:Profiler (nodes are q < 0.05 pathways, hypergeometric test). Pathways were merged in Enrichment Map