Until recently, AD patients were diagnosed based solely on clinical symptomatology, with a definitive neuropathological confirmation obtained postmortem by identifying the presence of two histopathological hallmarks associated with this disease, neurofibrillary tangles (NFTs) of hyperphosphorylated tau protein and senile plaques formed by beta-amyloid (Aβ) protein [2,3]. The gene discussed is MAPT; the disease is Alzheimer disease.