Plasma tau phosphorylated at threonine 181 and/or 231 (p‐tau181 and p‐tau231, respectively) are specific for AD pathology and lie on a continuum, with p‐tau231 more responsive at lower thresholds of Aβ pathology before there is global spread, whereas p‐tau181 shows greater sensitivity to a higher burden of Aβ.44, 45, 46, 47, 48, 49. The gene discussed is MAPT; the disease is Alzheimer disease.