Argyrophilic grain disease presenting as behavioral frontotemporal dementia.

Argyrophilic grain disease (AgD) is a frequent late-onset 4R tauopathy of old age characterized by the presence of profuse spindle-shaped argyrophilic grains (AGs). It is a neurodegenerative disorder that is clinically characterized by a slow progressive amnestic mild cognitive impairment similar to Alzheimer's disease. In rare instances, it is characterized as a behavioral-variant frontotemporal dementia (bv-FTD). In this study, we report a case with typical clinical and neuroimaging features of bv-FTD, who had autopsy findings consistent with a definitive diagnosis of AgD. We suggest that AgD might be included in the differential diagnosis of patients presenting with bv-FTD.
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Frontotemporal lobar degeneration: Study of a clinicopathological cohort.

Frontotemporal dementia results from different neurodegenerative diseases heterogeneous from a clinical, neuropathological and genetic point of view. Our main objective was to analyze the sociodemographic, clinical, neuropathological and molecular characteristics of cases with frontotemporal lobar degeneration from different Neurological Tissue Banks. FTD has been considered as a disease with onset below 65. However, diagnosis at higher ages is increasingly common. In our study, there was a correlation between symptoms and disease course with certain neuropathological diagnoses, with different distribution depending on age and sex. Combined pathology with Alzheimer's and vascular pathology was observed and presence of argyrophilic grains, with a different distribution in the different subgroups and a particular clinical and progression phenotype. Low percentage of APOE4 was detected. H1/H1 haplotype of the MAPT gene was the most frequent and appeared in relationship with 4R tauopathies. These results point to biologically significant differences between the different types of FTLD.

Argyrophilic Grain Pathology in Frontotemporal Lobar Degeneration: Demographic, Clinical, Neuropathological, and Genetic Features.

Frontotemporal lobar degeneration (FTLD) is a clinically, pathologically, and genetically heterogeneous group of disorders that affect the frontal and temporal lobes of the brain. FTLD classification distinguishes three main neuropathological groups: FTLD-tau, FTLD-TDP, and FTLD-FUS. As a four-repeat tauopathy, argyrophilic grain disease (AGD) is included in the FTLD-tau group. AGD may also appear in association with other neuropathological disorders. We describe the demographic, clinical, neuropathological, and genetic characteristics of a series of FTLD cases presenting with AGD. For this purpose, a clinico-pathological study of 71 autopsy-confirmed FTLD cases from different tissue banks was performed. AGD was found in 52.1% of FTLD cases. The presence of AGD increased with the increasing age (up to 88.9% in cases older than 80 years; p < 0.001) and was associated with higher ages at onset (p < 0.001) and death (p < 0.001). In AGD cases, progressive supranuclear palsy (PSP) was the most frequent clinical diagnosis (29.7%) and gait disturbance was the most common symptom (64.5%); behavioral and language symptoms were less frequent as compared with non-AGD cases (p = 0.055; p = 0.012). PSP was the most frequent neuropathological diagnosis among cases with AGD (32.4%). This group also showed less brain atrophy (p = 0.094) and higher prevalence of Alzheimer (p = 0.002) and vascular pathology (p = 0.047) as compared to the non-AGD group. We also observed that H1/H1 genotype was overrepresented in AGD cases (p = 0.018) and that there was no association with any specific APOE allele. A subanalysis of PSP cases according to the AGD status was carried out, yielding no significant differences.