Future projects should aim at identifying and deploying specific markers of disease activity and severity in FTLD, and we have previously reported the comparative diagnostic value of plasma NfL vs plasma p-tau in FTLD and Alzheimer disease.41 On the basis of work in dominantly inherited Alzheimer disease,42 longitudinal plasma NfL measurements may have better predictive ability for clinical decline than the cross-sectional measures we used. This evidence concerns the gene MAPT and Alzheimer disease.