MAPT and Alzheimer disease: In order to reduce sample sizes and improve efficacy for AD trials, targeted trials or sub-group selection trials which select participants based on genotype (e.g. APOE), cognitive status (e.g. Mini-Mental State Examination (MMSE)), and/or AD biomarkers (e.g. CSF Aβ and tau, or amyloid PET), have been recommended [5–7].