BACE1 and early-onset autosomal dominant Alzheimer disease: For example, Alzheimer's disease‐linked protease β‐site APP‐cleaving enzyme (BACE1) (Vassar et al, 1999; Yan et al, 1999), which has fundamental functions in the brain, is highly expressed in neurons, but not in astrocytes, microglia, or oligodendrocytes (Voytyuk et al, 2018).