According to the IWG-1 criteria, prodromal AD is defined by abnormal amyloid, tau, or FDG-PET or by hippocampal atrophy, while according to IWG-2 criteria, prodromal AD is defined by abnormal beta amyloid 1–42 and tau in cerebrospinal fluid (CSF) or an abnormal amyloid PET scan [7, 8]. The gene discussed is MAPT; the disease is hippocampal atrophy.