LDLR and Alzheimer disease: The additional knockout of ApoE does not affect the Aβ levels in Ldlr-deficient AD mice (APP/PS1; Katsouri and Georgopoulos, 2011), and this was confirmed by an in vitro study in astrocytes demonstrating that the clearance of Aβ is independent of ApoE (Basak et al., 2012).