Additionally, multiple studies have identified CSF biomarkers to be clinically relevant for early diagnosis of dementia, particularly high levels of amyloid-β (Aβ)42, Aβ40, total tau, and phosphorylated tau.15, –17 Extracellular amyloid plaques comprising Aβ peptides are regarded as an important neuropathologic feature of AD, with their assessment being typically performed by lumbar puncture or amyloid PET scans. The gene discussed is MAPT; the disease is Alzheimer disease.