The 7 candidate genes in GSE4757 were all significantly downregulated in AD (Figure 5B), wherein the differential expression of the SIX4 and TPX2 genes was the most significant in normal samples and disease samples (differential p values of 0.0055 and 0.007, respectively); thus, SIX4 was selected as the research object. Here, SIX4 is linked to Alzheimer disease.