As many gene variants can be associated with AD, and variants in the ApoE gene confer high risk for AD, we also screened these cell lines for and ApoE3 or ApoE4 genotype (Fig. 1q–t), demonstrating that the PSEN1 AD cell line also possessed an ApoE3/4 genotype conferring increased risk for AD, while the other cell lines maintained a neutral ApoE3/3 genotype. Here, APOE is linked to Alzheimer disease.