During recent years, novel mass spectrometry (MS) and antibody‐based methods have greatly contributed to our knowledge regarding the time course of different p‐tau species in fluids, helping to further understand their potential as biomarkers of AD pathology during disease progression (Barthelemy et al, 2019, 2020; Karikari et al, 2020; Lantero Rodriguez et al, 2020; Palmqvist et al, 2020; Suarez‐Calvet et al, 2020; preprint: Ashton et al, 2021a; Ashton, et al, 2021b). This evidence concerns the gene MAPT and Alzheimer disease.