Specifically, the ε4 allele of the APOE increases the risk of developing sporadic AD, with individuals carrying one ε4 allele having a 2- to 3-fold increased risk, and those with two ε4 alleles facing a 10- to 15-fold higher risk (Kim et al., 2009; Wijesinghe et al., 2016; Yamazaki et al., 2019; Narasimhan et al., 2024). The gene discussed is APOE; the disease is Alzheimer disease.