title: MAPT S305I mutation: implications for argyrophilic grain disease.
abstract: Frontotemporal lobar degeneration (FTLD) with mutations in the tau gene (MAPT) causes familial frontotemporal dementia with tau pathology. Many of these mutations result in morphological phenotypes resembling sporadic tauopathies, although, to date, no such cases mimicking argyrophilic grain disease (AgD) have been documented. We now present a case with a novel S305I MAPT mutation and a morphological phenotype showing resemblance to AgD. At the age of 39, the patient developed behavioural and personality changes and lack of verbal fluency with later poor performance on naming tasks and rigidity in the extremities. After a short disease course of 1.5 years, the patient died. A unique neuropathological phenotype with neuronal diffuse cytoplasmic tau immunoreactivity, oligodendroglial-coiled bodies, argyrophilic grains, and non-argyrophilic, but tau-immunopositive and ubiquitin-immunonegative pre-grains were observed, whereas classical neurofibrillary tangles, Pick bodies, and neuritic plaques were absent. The tau-positive abnormal structures were composed only of 4R-tau isoforms and, ultrastructurally, straight filaments. Neuronal loss was greatest in the medial temporal cortex, hippocampus, and amygdala. These pathological features resemble AgD. The novel S305I substitution has a strong effect on MAPT exon 10 splicing, thereby causing a striking increase in 4R-tau isoforms. Our observation not only widens the phenotypic spectrum of FTLD with MAPT mutation but also underpins the notion that the predominance of similar neuropathological findings in sporadic AgD cases may be viewed as features of a distinct disease entity.
authors: Institute of Neurology, Medical University of Vienna, Vienna, Austria.
authors: Gabor G
authors: GG
authors: Kovacs
authors: Alan
authors: A
authors: Pittman
authors: Tamas
authors: T
authors: Revesz
authors: Connie
authors: C
authors: Luk
authors: Andrew
authors: A
authors: Lees
authors: Eva
authors: E
authors: Kiss
authors: Peter
authors: P
authors: Tariska
authors: Lajos
authors: L
authors: Laszlo
authors: Kinga
authors: K
authors: Molnár
authors: Maria J
authors: MJ
authors: Molnar
authors: Markus
authors: M
authors: Tolnay
authors: Rohan
authors: R
authors: de Silva
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D003704:Dementia / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016875:tau Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: C054369:MAPT protein, human; D016875:tau Proteins