For the down-regulated AD-DEGs, only eight significant pathways were identified (Fig. 1 and Supplementary Table 3) including EIF2 Signalling (BH.pval = 3.98E-15, ratio = 64/210); Oxidative Phosphorylation (BH.pval = 2.00E-14, ratio = 39/92); Mitochondrial Dysfunction (BH.pval = 1.58E-11, ratio = 47/152); and Protein Ubiquitination (BH.pval = 7.92E-11, ratio = 63/254), Similarly, we identified 63 and nine significant canonical pathways for up- and down-regulated blood MCI-DEGs respectively. The gene discussed is MCIDAS; the disease is Alzheimer disease.