To further explore HERV-K as a possible marker for bvFTD TDP-43 pathology and to understand the link between serum and brain HERV-K levels, we measured the HERV-K env transcript expression in bvFTD with TDP-43 pathology and control brain (Table 1) in the SFC, a brain region affected by FTD, and the cerebellum, a brain region largely unaffected by FTD pathologies. Here, TARDBP is linked to behavioral variant of frontotemporal dementia.