In this study, we analyze plasma biomarkers in our clinical cohort of well-characterized dementia cases with three aims: (a) to establish the power of AD core, GFAP and NfL biomarkers to discriminate between underlying AD and FTD; (b) to examine the value of GFAP and NfL in distinguishing FTD cases from controls; and (c) to explore biomarker profiles in different FTD phenotypes, including genetically diagnosed cases. The gene discussed is NEFL; the disease is Alzheimer disease.