From a neuropathological perspective, AD is associated with several characteristic features, the most important being progressive and extensive atrophy of the cortex and hippocampus, the deposition of insoluble β-amyloid (Aβ) within extracellular neuritic plaques and the appearance of intracellular neurofibrillary tangles (NFTs), composed of hyperphosphorylated tau protein [1,2]. The gene discussed is MAPT; the disease is Alzheimer disease.