APOE and Alzheimer disease: Lastly, although ApoE-ε4 represents the strongest genetic risk factor for AD [49], as genetic research goes on, studies have found suggestive links between late-onset AD and a number of other genes, such as ABCA7, CLU, CR1, PICALM, PDL3, TREMZ, and SORL1 [50], that might influence spatial navigation performances.