Primary Feline Tauopathy : Clinical, Morphological, Immunohistochemical, and Genetic Studies

Abstract

Tauopathies are a group of neurodegenerative diseases where a specific protein called tau accumulates and forms aggregates in neurons and glial cells. In humans, these diseases can be caused by only this protein (primary) or in combination with another one (secondary). Primary tauopathies are common in humans but rare in animals. We analyzed the development of tau pathology in 16 cats of different ages. A female cat showed progressive mental status and gait abnormalities over a six-year period. Brain imaging revealed a progressive shrinkage of the brain (atrophy). Due to a poor prognosis, the cat was euthanized at the age of ten years. Evaluation of the brain tissue showed significant loss of neurons in the parietal cortex and Purkinje cells in the cerebellum. Immunohistochemistry identified abnormal tau protein aggregates in neurons (referred to as pre-tangles) and oligodendrocytes (referred to as coiled bodies). Genetic testing did not reveal any known genetic alteration associated with this disease. None of the other 15 cats studied showed similar clinical signs or brain changes. This is the first reported case of primary tauopathy in an adult cat that presented the first neurological signs when she was four years old.