“…The APOE 19q13.3 locus is a genetically heterogenous region within which complex haplotype structures, interactions, and compound genotypes have been identified (Templeton et al, 2005;Yu et al, 2007;Lescai et al, 2011;Lutz et al, 2016;Babenko et al, 2018;Kulminski et al, 2018Kulminski et al, , 2020aKulminski et al, ,b, 2021Zhou et al, 2019;Nazarian et al, 2022a,b). For instance, linkage disequilibrium (LD) and association studies have highlighted complex genetic structure in this locus that are statistically different between AD-affected and unaffected subjects (Kulminski et al, 2018(Kulminski et al, , 2020a. In addition, stratified 10.3389/fnagi.2022.1023493 analyses have identified sets of interactions and compound genotypes in the APOE locus of the ε2and ε4-carriers, which may modify the effects of these alleles on AD risk and, to some extent, justify their incomplete penetrance (Nazarian et al, 2022a,b).…”