18 Using this method, we previously showed that bisecting GlcNAc is elevated in CSF in patients with Alzheimer’s disease.17 Importantly, glycan levels correlated with CSF levels of total tau (tTau) and phosphorylated tau-181 (pTau181) already in individuals with subjective cognitive impairment (SCI). The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.