MAPT and early-onset autosomal dominant Alzheimer disease: Biomarkers for Alzheimer’s disease, including cerebrospinal fluid (CSF) and plasma levels of Aβ40, Aβ42, total tau (t-tau), and phosphorylated tau (p-tau-181/217), as well as neuroimaging measures such as PET and MRI, are important for an accurate clinical diagnosis of dementia, determination of disease progression, and serve as key outcome measures for clinical trials of novel therapeutics.