APOE and Alzheimer disease: Not surprisingly, due to the e4 allele’s well-known status as the main genetic driver of AD, we do not observe any improvement of the MetaGRS in APOE e4 carriers based on the Cox hazard model estimates (C-index = 0.578 for AD PCA-GRS, C-index = 0.578 for MetaGRS in Figure 4B, HR = 1.233 for AD PCA-GRS, HR = 1.232 for MetaGRS in Table 2).