For example, bisecting GlcNAc, which is the GlcNAc branch synthesized by GnT-III, is involved in Alzheimer’s disease because the loss of GnT-III resulted in both the reduction of amyloid-β deposition and improvement of cognitive function in Alzheimer’s disease mouse models, owing to the impaired function of amyloid-β-producing enzyme BACE114,15. The gene discussed is MGAT3; the disease is Alzheimer disease.