PPARA and Huntington disease: Pathway analysis of these 519 differentially methylated sites suggests that increased methylation (positive z-score) may be associated with synaptogenesis signaling, PFKB4 signaling, Gs alpha signaling, and PPARɑ/RXRɑ activation, while decreased methylation (negative z-score) may be associated with neurodegenerative pathways (Huntington’s Disease), opioid signaling, and IL-15 production (Fig. 1d, Supplemental Table S3).