ABCB1 and Alzheimer disease: In studies, it is argued that depending on the expression, localization, potency, and multispecificity of this transporter subtype act as an important barrier to the xenobiotics' entrance to the brain.42Studies report that ABCB1 is required for normal clearance of Aβ.43It is reported that the accumulation of CAA and Aβ increases the risk of developing AD associated with impaired ABCB1 activity.