title: Argyrophilic grain disease is a sporadic 4-repeat tauopathy.
abstract: Argyrophilic grain disease (AGD) was first reported as an adult-onset dementia, but recent studies have emphasized personality change, emotional imbalance, and memory problems as clinical features of AGD. AGD is characterized by spindle- or comma-shaped argyrophilic grains in the neuropil of entorhinal cortex, hippocampus, and amygdala. Immunohistochemistry with monoclonal antibodies specific to tau isoforms with four (4R) or three (3R) repeats in the microtubule-binding domain showed immunostaining of grains with 4R, but not 3R, tau antibodies, suggesting that AGD was a 4R tauopathy. The tau isoform composition of AGD was confirmed with densitometric analysis of Western blots of sarkosyl-insoluble tau from the medial temporal lobe of AGD brains with a range of concurrent neurofibrillary pathology and compared with Alzheimer controls. The 4R/3R ratio was 1 or less for Alzheimer disease; the 4R/3R ratio was more than 1 for AGD, decreasing with increasing neurofibrillary pathology and demonstrating that insoluble tau in AGD was enriched in 4R tau. The frequency of the extended tau haplotype was not different in AGD compared to other sporadic 4R tauopathies, progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Furthermore, AGD occurred in PSP and CBD more frequently than in dementia controls, including Alzheimer disease. These results suggest that AGD, PSP and CBD are 4R tauopathies that share common pathologic, biochemical, and genetic characteristics.
authors.affiliation: Department of Pathology, Mayo Clinic, Jacksonville, Florida 32224, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Togo
authors.forename: Naruhiko
authors.initials: N
authors.lastname: Sahara
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Yen
authors.forename: Natalie
authors.initials: N
authors.lastname: Cookson
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishizawa
authors.forename: Mike
authors.initials: M
authors.lastname: Hutton
authors.forename: Rohan
authors.initials: R
authors.lastname: de Silva
authors.forename: Andrew
authors.initials: A
authors.lastname: Lees
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Dickson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology; D000911:Antibodies, Monoclonal; D001479:Basal Ganglia / Q000737:chemistry / Q000473:pathology; D015153:Blotting, Western; D001933:Brain Stem / Q000737:chemistry / Q000473:pathology; D005260:Female; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D007150:Immunohistochemistry; D007536:Isomerism; D008297:Male; D016622:Silver Staining; D013494:Supranuclear Palsy, Progressive / Q000473:pathology; D024801:Tauopathies / Q000235:genetics* / Q000473:pathology*; D013702:Temporal Lobe / Q000737:chemistry / Q000473:pathology*; D016875:tau Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D016875:tau Proteins