Amyloid beta (Aβ) deposition in Alzheimer’s disease has been shown to be inversely correlated with ABCB1 expression in the brains of elderly people without dementia, which may indicate that age-related ABCB1 deficiency may be involved in the pathogenesis of Alzheimer’s disease [138,143]. The gene discussed is ABCB1; the disease is early-onset autosomal dominant Alzheimer disease.