SELECTIVE EXPRESSION OF SER-199 202 PHOSPHORYLATED TAU IN A CASE OF FRONTOTEMPORAL DEMENTIA/

We examined a 65-year-old patient with clinicopathological features th at met the criteria of frontotemporal dementia (FTD), particularly fro ntal lobe degeneration (FLD), He came from a family with concentrated occurrence of dementia symptoms in the presenium. Neuropathological ex amination disclosed brain atrophy locally pronounced on the frontotemp oral lobes with characteristic neuronal loss, microvacuolation and ast rocytic gliosis. There were no pathological hallmarks such as senile p laques, Pick bodies (PBs), achromatic cells and neurofibrillary tangle s. Precise separation of FTD from Pick disease (PD) and motor neuron d isease with dementia (MNDD) has not pet been established, and they are included in one spectrum, Antibodies against paired helical filament tau protein demonstrated immunopositive cytoskeletal structures within the neurons as well as the glial cells in the brain of the present ca se. They were selectively stained with tau 199/202 but not tau 396, wh ich were provided newly to recognize phosphorylation at Ser 199/302 or Ser 396 in tan, respectively. We investigated tau pathology in the pr esent case in comparison to 8 cases with PD that were clinicopathologi cally confirmed. Neither tau 199/202 nor tau 396 stained the CNS struc tures in PD cases with few PBs, while both stained evidently these as well as PBs in PD cases associated with manly PBs: so that the present case could be distinguished from PD on the basis of the immunoreactiv ity to site-specific phosphorylated tau. Our result suggests that FTD, especially familial FLD type might involve unique tau pathology, no m atter whether FLD is a distinct entity from PD, or a variant form in t he wide FTD spectrum including PD and MNDD and other related disorders .