MAPT and Alzheimer disease: In AD, the CSF core biomarkers; the 42 amino acid long Aβ peptide (Aβ1–42), total tau protein (T‐tau), and phosphorylated tau protein (P‐tau),33 provides robust discrimination of patients with AD compared to controls as well as patients with mild cognitive impairment due to AD compared to stable mild cognitive impairment.34 Identifying additional CSF biomarkers would be of importance for the understanding of pathophysiological processes involved in neurodegenerative diseases.