To better understand the genetic architecture of cognitive decline, we conducted genome-wide meta-analyses on older adults in three APOE genotype groups: APOE2 carriers (APOE 2/2, 2/3), APOE3 homozygotes (APOE 3/3), and APOE4 carriers (APOE 3/4, 4/4). The gene discussed is APOE; the disease is Mental deterioration.