BACE1 and early-onset autosomal dominant Alzheimer disease: Astrocytes may not only be involved in the clearance of Amyloid beta peptides (Aβ) in Alzheimer's disease (AD), but appear to produce N-terminally truncated Aβ (Aβn−x) independently of BACE1, which generates the N-Terminus of Aβ starting with Asp1 (Aβ1−x).