Plasma P-tau181 was shown to be elevated in preclinical AD and further elevated in the MCI and dementia phases in research by Janelidze et al. They demonstrated that Plasma P-tau181 had accuracy comparable to Tau PET and CSF P-tau181, distinguished AD dementia from non-AD neurodegenerative illnesses, and identified AD neuropathology in a cohort with autopsy confirmation (276). This evidence concerns the gene MAPT and Alzheimer disease.