APOE and Alzheimer disease: Furthermore, studies indicate that expression of the APOE ε4-encoding variant of apolipoprotein E (APOE) (Lin et al., 2018; Nuriel et al., 2017) is the greatest genetic risk factor for late onset AD (LOAD), which, along with many other LOAD risk genes and genes causing familial AD (Hung and Livesey, 2018; Kwart et al., 2019), converge to alter EAL function (Gao et al., 2018; Karch and Goate, 2015; Pimenova et al., 2018; Van Acker et al., 2019).