ARAP1 and Alzheimer disease: For the larger iOPC cluster, there were 5,578 DEGs (Fig. 4A, Table S17), 30 of which are known AD GWAS loci; interestingly, most of them were upregulated in the 4/4 lines compared with the 3/3 lines (Fig. 4A,4B), with the exceptions of IGF1R, IDUA, SORT1, ALCAM, MGMT, FGF12 and ARAP1.