The well-established AD biomarkers include cerebrospinal fluid (CSF) biomarkers of β-amyloid 42 (Aβ42), total tau (T-tau), and phosphorylated tau (P-tau); positron emission tomography (PET) measurements of Aβ and tau; and structural magnetic resonance imaging (MRI) measurements [3–5], which are increasingly used to support the diagnosis of AD in research, clinical practice and drug development and have become part of the newly revised early diagnostic criteria for AD [6, 7]. The gene discussed is MAPT; the disease is Alzheimer disease.