Our finding that bisecting GlcNAc was generally increased in Alzheimer’s disease is consistent with an upregulation of the sole synthesizing enzyme for this epitope (N-acetylglucosaminyltransferase III), which has been reported to be the case in Alzheimer’s disease.38 However, levels of specific glycopeptides may be more specific markers for Alzheimer’s disease pathology. The gene discussed is MGAT3; the disease is early-onset autosomal dominant Alzheimer disease.