MAPT and Alzheimer disease: The diagnosis of AD is based on clinical examination, interview with the patient and relatives, neuropsychological tests (e.g., mini-mental state examination, MMSE), imaging (structural Magnetic Resonance Imaging, MRI, FDG-PET, amyloid PET), and finally lumbar puncture with the quantification of CSF biomarkers Aβ42, Aβ40 (together with the ratio of Aβ42/Aβ40), total tau (t-tau), and phosphorylated tau on threonine 181 (p-tau).