MAPT and early-onset autosomal dominant Alzheimer disease: CSF biomarkers are informative, sensitive and specific for the detection of Alzheimer’s disease (AD) in clinical and research settings from early stages of the disease.1,2 The recent development of plasma biomarkers is dramatically changing the AD scenario, as they are scalable tools to aid clinical evaluation and trial recruitment.3,4 Phosphorylated tau (p-tau) species stand at the forefront of emerging AD blood tests, exhibiting superior accuracy in diagnosis and specificity for the disease compared to the amyloid-beta (Aβ) 42/40 ratio or other suggested biomarkers.5-9