MAPT and early-onset autosomal dominant Alzheimer disease: Finally, we show that plasma P-tau181 correlated to both CSF T-tau and P-tau181 in ADAD, consistent with other sporadic Alzheimer's disease cohorts.7,14 Altogether, our findings support the previous large amount of data that have highlighted plasma P-tau as an actual biomarker of Alzheimer's disease-related CNS tau pathology.