TNF and Parkinson disease: In addition, vascular processes [tumor necrosis factor signaling, vascular endothelial growth factor (VEGF) signaling, platelet activation, and the complement cascade] were enriched in cluster 3, while cluster 4 was enriched for genes implicated in age-related disorders such as Parkinson’s disease, amyotrophic lateral sclerosis, Huntington’s disease, and Alzheimer’s diseases (Fig. 3E and table S7).