MAPT and prion disease: The aim of our study was to examine levels of selected protein CSF biomarkers in neuropathologically confirmed cases of prion diseases, AD, frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP), frontotemporal lobar degeneration with tau inclusions (FTLD-tau), and DLB and to determine which of the aforementioned CSF biomarkers, or their ratios, would be helpful in the differential diagnosis of dementia, in cases with overlapping clinical symptoms.