PPARA and Parkinson disease: The gene set of “Alzheimer’s disease” was mapped to the pathways of “Oxidative phosphorylation” and “Parkinson’s disease” with an effect of 35% and adjusted p-value < 0.001; and the “stromal stem cells” was mapped to the peroxisome proliferator-activated receptors (PPAR) and p53 signaling pathways with an effect of 10% and adjusted p-value of 0.029.