Granular aggregations containing tau truncated at Glu391 are detected within the somatodendritic compartment of AD brains but not in age-matched non-demented controls [145], Glu391-truncated tau is present in PHF isolated from AD tissue [146-148] and tau-truncated at Asp421 associates with neurofibrillary pathology in AD brains [149-151]. This evidence concerns the gene MAPT and Alzheimer disease.