Recent updated Braak staging of Alzheimer’s disease (AD) implicates the brainstem as the first site of tau-related pathology, with the locus coeruleus (LC) the first nucleus to demonstrate signs of pretangles (i.e., precursors to neurofibrillary tangle pathology) (Braak and Del Tredici 2015). This evidence concerns the gene MAPT and Alzheimer disease.