ABCC1 and Alzheimer disease: Brain clearance of the neurotoxic Aβ peptides is partly mediated by the efflux transporters such as P‐gp, ABCC1, and ABCA1.[69, 131, 132] In AD patients, Aβ clearance (efflux) from the brain is reduced by ≈30%.[133] Decreased activity or function of these ABC efflux transporters could contribute to the lower efflux of Aβ.