APOE and Alzheimer disease: Using a parental iPSC line with APOE ε4/ε4 from a sporadic AD patient (Par-E4/4) and the isogenic iPSC line with APOE ε3/ε3 (Iso-E3/3)19, we tested whether converting APOE4 to APOE3 could ameliorate APOE4-related phenotypes in iPSC-derived organoids.