APOE and Alzheimer disease: The APOE4 allele is recognized as a significant genetic risk factor for LOAD (Uddin et al. 2018; Yamazaki et al. 2019), with 56% of AD patients in the United States carrying one copy of the APOE4 allele and 11% carrying two copies (Alzheimer's Association 2023; Rajan et al. 2021).