BACE1 and Alzheimer disease: Several proteins involved in AD pathogenesis, including tau, BACE‐1, and APP, have been found to have altered glycosylation pattern in AD 12, 13, 14, and both N‐ and O‐glycosylation pathways appear to be affected 15, including O‐GlcNAcylation, a protein modification involving addition of one single monosaccharide, N‐acetylglucosamine (GlcNAc), to the protein 16.