SNCA and Parkinson disease: For other genes that are deemed as causative factors in PD, their overall expression levels in neuron were upregulated for Snca (average log2FC = 0.5373), and downregulated for Slc18a2 (average log2FC = −0.2616) and Aldh1a1 (average log2FC = −0.2164) (Fig. 7D, Supplementary Fig. 8B, C, Table S4).