Some studies have found that CSF tau is associated with hippocampal atrophy, while CSF amyloid is not.16 Others have reported associations between both core biomarkers and hippocampal atrophy17,18 or with whole brain volume—amyloid in controls and p-tau in Alzheimer’s disease dementia.19 CSF amyloid, not p-tau, was also associated with ventricular enlargement in preclinical Alzheimer’s disease.20-23. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.