P3-186 Concurrent Alzheimer's disease-related pathology lowers the threshold for developing dementia in argyrophilic grain disease

Abstract

Background: Argyrophilic grain disease (AGD) constitutes a neurodegenerative disorder that occurs in the brains of the elderly and affects 5% of all patients with dementia, tan-protein-containing lesions known as argyrophilic grains in neuronal processes and coiled bodies in oligodendrocytes characterize this disease. Dementia is encountered in only a subset of cases that display the morphological pattern of AGD at autopsy. Objective: To determine the role of concurrent Alzheimer's disease (AD)-related pathology for the development of dementia in AGD patients. Methods: Autopsy brains from 30 demented and 49 non-demented AGD patients, from 46 AD patients and from 86 non-demented controls without AGD were staged for the distribution of AD-related neurofibrillary changes and amyloid 13-protein (AI3) deposits. To identify differences in the distribution of AD-related pathology between demented and non-demented AGD cases, and to differentiate the pattern of AD-related changes in AGD cases from that seen in AD and non-demented controls, we compared the distribution of AI3-deposits and neurofibrillary changes among these groups of cases. Differences in the stages of the distribution of neurofibrillary changes and A[3-deposits among these groups were analyzed statistically. Conclusions: Demented AGD patients exhibited significantly higher stages of AD-related AI3-deposition and neurnfibrillary tangle pathology as compared to non-demented AGD cases, but significantly lower stages of both lesions compared to AD without AGD. In conclusion, AGD is a clinically relevant neurodegenerative entity that significantly lowers the threshold for developing dementia when it is associated with AD-related pathology.