This FTD cohort with right temporal variant FTD and semantic dementia patients had a high probability of underlying TAR DNA-binding protein 43 (TDP-43) pathology,15 which is associated with increased NfL levels.16 As in FTD patients the NfL concentration is significantly higher compared to other neurodegenerative diseases, in particular those FTD patients with underlying TDP-43 pathology, this FTD cohort has the highest likelihood for detection of NfL in urine. The gene discussed is TARDBP; the disease is semantic dementia.