To test the expression level and diagnostic value of the genes contained in these line diagram models, external validation of nine genes was carried out using the GSE122063 (Figures 4G–J), GSE118553 (Supplementary Figures 1A–D), GSE44768 (Supplementary Figures 1E–H), and GSE44770 (Supplementary Figures 1I–L) datasets, and the results showed that the difference trend of SERPINA3 and GFAP was relatively stable, and their expression was upregulated in AD samples. The gene discussed is SERPINA3; the disease is Alzheimer disease.