GFAP is one of the cytoskeletal filament proteins in astrocytes, and its production and release are increased on reactive astrocytosis as a consequence of neurodegeneration.14 15 Although NfL and GFAP are cross-disease markers, rather than disease specific, there is emerging evidence that both NfL and GFAP can be of diagnostic value for differentiating bvFTD from other dementia types15 16 and from PPD.17, 23 Despite the significance of these investigations, they often featured small sample sizes and included both genetic and sporadic bvFTD. This evidence concerns the gene NEFL and dementia.