Variant Gerstman-Straussler syndrome with the P105L prion gene mutation: an unusual case with nigral degeneration and widespread neurofibrillary tangles

We present here a case of variant Gerstmann-Straussler syndrome (GSS) with a codon 105 mutation of the prion protein gene. A 57-year-old woman develop ed dementia and gait disturbance dissimilar to the spastic paraparesis that is observed in most cases with codon 105 mutation. The clinical course of the disease in this case was 12 years. The brain weighed 900 g, and the fro ntal lobe, pallidum and thalamus were markedly atrophic. Severe neuronal lo ss was observed in the deep layer of the frontal and temporal cortices, and fibrillary gliosis and a marked loss of neurons was observed in the globus pallidus, thalamus and substantia nigra. Many amyloid plaques and some bal looned neurons were present in the frontal, temporal and parietal cortices. However, no spongiform changes were seen. The cerebellum was relatively we ll preserved. Numerous neurofibrillary tangles (NFTs) were recognized in th e cerebral cortices, and scattered NFTs were observed in the basal nucleus of Meynert, thalamus, substantia nigra, periaqueductal gray matter, raphe n uclei and locus ceruleus. The case presented here indicates the presence of variations in the pathological findings of cases with codon 105 mutation, and that the formation of cortical and brain stem NFTs might have something to do with the duration of illness and/or the degree of brain tissue destr uction that had occurred.