ALAS1 levels were significantly reduced in EOAD neurons carrying the PSEN1 mutation (AD PSEN1 DIF, Figure 3A) and LOAD neurons carrying APOE4 allele (AD APOE4 DIF, Figure 3A), compared to their respective control neurons (HC M DIF & HC F DIF, Figure 3A). Here, PSEN1 is linked to Alzheimer disease.