By leveraging large cohorts of participants with sporadic or genetic bvFTD, nfvPPA, svPPA, CBS or PSP-RS, and clinically normal individuals with or without FTD-causing mutations, we conducted a head-to-head comparison of plasma GFAP and NfL to elucidate their respective biomarker capabilities. The gene discussed is NEFL; the disease is behavioral variant of frontotemporal dementia.