BACE1 (beta-site APP cleaving enzyme-1), a protease responsible for the production of amyloid-beta (Aβ) in AD, is heavily modified with bisecting GlcNAc [16,17], and BACE1 without bisecting GlcNAc is relocated to lysosomal compartments, leading to improvement of the AD pathology in the brains of GnT-III KO mice [16]. Here, MGAT3 is linked to Alzheimer disease.