MAPT and early-onset autosomal dominant Alzheimer disease: The LC is also one of the first brain sites to show, in otherwise healthy individuals, (a) pretangle tau material that is later colocalized with insoluble tau tangles and (b) synuclein inclusions, which are the hallmarks of the neuropathology of Alzheimer’s diseases (AD) and Parkinson’s disease (PD), respectively (17, 18).