PCA revealed that the contribution ratio of PC1 likely derived from multiple environmental effects was highest (57.6%), while those of PC2 likely derived from differences between healthy (normal) and ALS disease (with mutant SOD1) and PC3 likely derived from a cell-autonomous effect caused by the clear separation of each primary cultured microglial cell were 16.4% and 10.5%, respectively (Figure 7E). The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.