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Gerstmann–Sträussler–Scheinker disease (GSS) is a rare neurodegenerative illness that belongs to the group of hereditary or familial Transmissible Spongiform Encephalopathies (TSE). Due to the presence of different pathogenic alterations in the prion protein (PrP) coding gene, it shows an enhanced proneness to misfolding into its pathogenic isoform, leading to prion formation and propagation. This aberrantly folded protein is able to induce its conformation to the native counterparts forming amyloid fibrils and plaques partially resistant to protease degradation and showing neurotoxic properties. PrP with A117V pathogenic variant is the second most common genetic alteration leading to GSS and despite common phenotypic and neuropathological traits can be defined for each specific variant, strikingly heterogeneous manifestations have been reported for inter-familial cases bearing the same pathogenic variant or even within the same family. Given the scarcity of cases and their clinical, neuropathological, and biochemical variability, it is important to characterize thoroughly each reported case to establish potential correlations between clinical, neuropathological and biochemical hallmarks that could help to define disease subtypes. With that purpose in mind, this manuscript aims to provide a detailed report of the first Spanish GSS case associated with A117V variant including clinical, genetic, neuropathological and biochemical data, which could help define in the future potential disease subtypes and thus, explain the high heterogeneity observed in patients suffering from these maladies.

GPI anchorless prion diseases (GPIALPs) show numerous coarse prion protein (PrP) deposits in the CNS but neuropil spongiform changes are mild and the incidence of dementia is low. Here, we examined differences in resident microglial phenotypes between GPIALP (D178fs25) and the other prion diseases Gerstmann-Sträussler-Scheinker (GSS) disease and sporadic Creutzfeldt-Jakob disease (sCJD) with respect to homeostasis and activation. Immunohistochemistry was performed on 2 GPIALP (D178fs25), 4 GSS (P102L), and 4 sCJD cases. Homeostatic microglia expressing TMEM119 and P2RY12 were preserved in GPIALP compared to GSS and sCJD. Microglia/macrophage activation in GSS and sCJD was associated with the extent of spongiform change. Immunoelectron microscopy revealed TMEM119 and P2RY12 in PrP plaque cores. Activated microglia/macrophages expressing HLA-DR and CD68 were predominant in GSS and sCJD whereas in GPIALP, homeostatic microglia were retained and activated microglia/macrophages were rarely observed. These data suggest that PrP deposition in GPIALP is less toxic and that microglia may be immune-tolerant to PrP deposition. This may be associated with milder tissue damage and a low incidence of dementia. Whereas microglia/macrophage activation is considered to be a reaction to tissue injury, this study shows that the degree of microglia/macrophage activity might influence the extent of tissue damage.

In human neurodegenerative diseases associated with the intracellular aggregation of Tau protein, the ordered cores of Tau filaments adopt distinct folds. Here, we analyze Tau filaments isolated from the brain of individuals affected by Prion-Protein cerebral amyloid angiopathy (PrP-CAA) with a nonsense mutation in the PRNP gene that leads to early termination of translation of PrP (Q160Ter or Q160X), and Gerstmann–Sträussler–Scheinker (GSS) disease, with a missense mutation in the PRNP gene that leads to an amino acid substitution at residue 198 (F198S) of PrP. The clinical and neuropathologic phenotypes associated with these two mutations in PRNP are different; however, the neuropathologic analyses of these two genetic variants have consistently shown the presence of numerous neurofibrillary tangles (NFTs) made of filamentous Tau aggregates in neurons. We report that Tau filaments in PrP-CAA (Q160X) and GSS (F198S) are composed of 3-repeat and 4-repeat Tau isoforms, having a striking similarity to NFTs in Alzheimer disease (AD). In PrP-CAA (Q160X), Tau filaments are made of both paired helical filaments (PHFs) and straight filaments (SFs), while in GSS (F198S), only PHFs were found. Mass spectrometry analyses of Tau filaments extracted from PrP-CAA (Q160X) and GSS (F198S) brains show the presence of post-translational modifications that are comparable to those seen in Tau aggregates from AD. Cryo-EM analysis reveals that the atomic models of the Tau filaments obtained from PrP-CAA (Q160X) and GSS (F198S) are identical to those of the Tau filaments from AD, and are therefore distinct from those of Pick disease, chronic traumatic encephalopathy, and corticobasal degeneration. Our data support the hypothesis that in the presence of extracellular amyloid deposits and regardless of the primary amino acid sequence of the amyloid protein, similar molecular mechanisms are at play in the formation of identical Tau filaments.

BACKGROUND: Gerstmann-Struassler-Scheinker disease is one of the familial prion diseases secondary to mutations in the prion protein gene (PRNP). The clinical phenotype has a diverse spectrum and might show variation among cases with the same genotype. Herein we would like to report a patient with G131V mutation in the PRNP gene, who was initially considered to harbor familial Alzheimer's disease, based on the family history, clinical presentation and imaging findings. METHODS: A case with a G131V mutation in the PRNP gene is reported, and the literature is reviewed. RESULTS: A 35-year-old male presented with personality changes, behavioral disturbances and cognitive complaints. A similar clinical phenotype was reported in the patient's father, a paternal uncle and a paternal aunt. In conjunction with the observation of mild cerebral atrophy on magnetic resonance imaging and hypometabolism in bilateral temporal and parietal lobes on positron emission tomography studies, the diagnosis was initially considered as familial Alzheimer's disease. However, whole exome sequencing of the index patient, confirmed with Sanger sequencing in his father and uncle revealed the presence of a heterozygous G131V variant in the PRNP gene. CONCLUSION: To the best of our knowledge, this is the third report in the literature with G131V mutation in PRNP gene. Although ataxia and extrapyramidal findings accompanied dementia in patients reported in the prior literature, the members of the family reported herein primarily demonstrated cognitive impairment, underscoring the importance of genetic workup in familial early-onset dementia patients, regardless of clinical and imaging features suggestive of alternative pathologies.

Gerstmann-Sträussler-Scheinker (GSS) disease with P102L mutation and familial Creutzfeldt-Jakob disease (CJD) with V180I mutation are 2 major hereditary prion diseases in Japan. GSS and some familial CJD [V180I] exhibit characteristic prion protein (PrP) plaques. Overexpression of the astrocytic water channel proteins aquaporin (AQP) 1 and AQP4 was recently reported in sporadic CJD. To clarify the pathological characteristics of AQP1 and AQP4 in prion disease patient brains with plaque-type deposition, we investigated 5 patients with GSS, 2 patients with CJD [V180I], and 2 age-matched control cases without neurological diseases using immunohistochemistry and double immunofluorescence methods. We demonstrated that there is the intense expression of AQP1 and AQP4 around prion plaques, especially in distal astrocytic processes deep inside these plaques. Similar results have been reported in the senile plaques and ghost tangles of Alzheimer disease brains and a protective role of AQP4 in which AQP4 is redistributed toward the plaques and works as a barrier against the deleterious effects of these plaques has been suggested. Our results, which show a similar clustering of AQPs around PrP plaques, therefore support the possibility that AQPs also have a protective role in plaque formation in prion diseases.

Prion protein (PrP) aggregation and formation of PrP amyloid (APrP) are central events in the pathogenesis of prion diseases. In the dominantly inherited prion protein amyloidosis known as Gerstmann–Sträussler–Scheinker (GSS) disease, plaques made of PrP amyloid are present throughout the brain. The c.593t > c mutation in the prion protein gene (PRNP) results in a phenylalanine to serine amino acid substitution at PrP residue 198 (F198S) and causes the most severe amyloidosis among GSS variants. It has been shown that neurodegeneration in this disease is associated with the presence of extracellular APrP plaques and neuronal intracytoplasmic Tau inclusions, that have been shown to contain paired helical filaments identical to those found in Alzheimer disease. Using cryogenic electron microscopy (cryo-EM), we determined for the first time the structures of filaments of human APrP, isolated post-mortem from the brain of two symptomatic PRNP F198S mutation carriers. We report that in GSS (F198S) APrP filaments are composed of dimeric, trimeric and tetrameric left-handed protofilaments with their protomers sharing a common protein fold. The protomers in the cross-β spines consist of 62 amino acids and span from glycine 80 to phenylalanine 141, adopting a previously unseen spiral fold with a thicker outer layer and a thinner inner layer. Each protomer comprises nine short β-strands, with the β1 and β8 strands, as well as the β4 and β9 strands, forming a steric zipper. The data obtained by cryo-EM provide insights into the structural complexity of the PrP filament in a dominantly inherited human PrP amyloidosis. The novel findings highlight the urgency of extending our knowledge of the filaments' structures that may underlie distinct clinical and pathologic phenotypes of human neurodegenerative diseases.

Gerstmann-Sträussler-Scheinker disease (GSS) is a rare genetic prion disease. Unlike sporadic Creutzfeldt-Jakob disease, GSS has diverse clinical phenotypes, including slowly progressive cerebellar ataxia. Due to this clinical feature and the extreme rarity of GSS, the disease can be misdiagnosed as hereditary cerebellar ataxia.We present the first familial cases of GSS in South Korea. Previously affected family members were misdiagnosed with hereditary cerebellar ataxia. Two siblings (patients #1 and #2) of this family were genetically diagnosed with P102L mutation GSS. Another sibling (patient #3) was not genetically confirmed, but based on the clinical course and diffusion-weighted imaging (DWI), the diagnosis of GSS will be certain. Despite the same genetic mutation, these siblings showed different clinical phenotypes of GSS.We genetically confirmed familial cases of GSS in South Korea. Although the disease is extremely rare, the PRNP gene test should be considered in undiagnosed autosomal dominant hereditary cerebellar ataxia. Phenotypical variability of GSS may be reflected in DWI of the early phase of the disease.

Gerstmann-Sträussler-Scheinker disease (GSS) is a rare neurodegenerative illness that belongs to the group of hereditary or familial Transmissible Spongiform Encephalopathies (TSE). Due to the presence of different pathogenic alterations in the prion protein (PrP) coding gene, it shows an enhanced proneness to misfolding into its pathogenic isoform, leading to prion formation and propagation. This aberrantly folded protein is able to induce its conformation to the native counterparts forming amyloid fibrils and plaques partially resistant to protease degradation and showing neurotoxic properties. PrP with A117V pathogenic variant is the second most common genetic alteration leading to GSS and despite common phenotypic and neuropathological traits can be defined for each specific variant, strikingly heterogeneous manifestations have been reported for inter-familial cases bearing the same pathogenic variant or even within the same family. Given the scarcity of cases and their clinical, neuropathological, and biochemical variability, it is important to characterize thoroughly each reported case to establish potential correlations between clinical, neuropathological and biochemical hallmarks that could help to define disease subtypes. With that purpose in mind, this manuscript aims to provide a detailed report of the first Spanish GSS case associated with A117V variant including clinical, genetic, neuropathological and biochemical data, which could help define in the future potential disease subtypes and thus, explain the high heterogeneity observed in patients suffering from these maladies.

Introduction Different studies have shown that solar and geomagnetic activities (GMAs) affect human health outcomes, especially cardiovascular systems being the most clearly impacted. Aim To analyse the associations of geomagnetic storms (GSs) and other space weather events with morbidity from acute myocardial infarction (AMI) during the period 2000–2015. Methods To evaluate the influence of space weather variables, we used adjusted rate ratios (RRs), their 95% confidence intervals, and p-value of coefficients in the Poisson regression model. Results 12330 AMI cases (men and women n = 6942 and 5388, respectively) were registered. The study revealed that a higher risk of AMI and were related to the period of 3 days before GS—a day after GS, and a stronger effect was observed during the spring-autumn period. The strongest effect of high-speed solar wind (HSSW) was observed on the day of the event. We found significant associations between the risk of AMI and the occurrence of Solar flares (SFs) during GSs. We also found a statistically significant increase in rate ratios for all AMIs between the second and fourth days of the period of interplanetary coronal mass ejections (ICMEs). Key messages This Abstract is a part of PostDoc project. One of the goal of this project is to determine and evaluate heliogeophysical factors that have an effect on morbidity and mortality from CVD.

Anle138b is an anti-aggregating compound previously shown to delay the onset of scrapie, a transmissible prion disease, although its in vivo efficacy against other prion disease subtypes has not been fully assessed. TgGSS mice that model Gerstmann-Straussler-Scheinker disease (GSS) via expression of mouse PrPA116V accumulate PrP amyloid plaques in their brains and develop progressive ataxia leading to death in ~160 days. When allowed to feed on food pellets containing anle138b from weaning until death, the brains of TgGSS mice displayed significant reductions in PrP plaque burden, insoluble PrP, and proteinase K-resistant PrPSc at end stage, compared with TgGSS mice allowed to feed on placebo food pellets. Despite these effects on biological markers of disease, there was no difference in the onset of symptoms or the age at death between the two treatment groups. In contrast, scrapie-inoculated wild-type mice treated with anle138b survived nearly twice as long (254 days) as scrapie-inoculated mice fed placebo (~136 days). They also displayed greater reductions in insoluble and PK-resistant PrPSc than TgGSS mice. Although these results support an anti-aggregating effect of anle138b, the discordance in clinical efficacy noted between the two prion disease models tested underscores the pathophysiological differences between them and highlights the need to consider differences in susceptibilities among prion subtypes when assessing potential therapies for prion diseases.

Gerstmann-Sträussler-Scheinker (GSS) syndrome is a devastating hereditary prion disease, presenting in 4th-5th decade with progressive ataxia and dementia. Pathogenic variants in the PRNP gene lead to aggregation of misfolded prion protein which results in neurodegeneration and death within a few years of onset. A key feature of prion disorders is conversion of normal prion protein (PrPc) into its misfolded form (PrPSc). Genetic modifiers include methionine at position 129 in prion protein and octapeptide repeats. We present an Indian kindred with c. 305CT, p.Pro102Leu mutation in PRNP gene causing GSS in multiple members and discuss the impact of the polymorphism at position 129 on the severity of illness.

A common presentation of the P102L prion protein mutation is Gerstmann-Straussler-Scheinker syndrome. Rudge et al. show that serial measurement of lower limb thermal thresholds predicts, within a relatively narrow time window, conversion to the symptomatic phase of the disease, and that synaptic deposition of PrPSc in the spinal cord underpins the pathology., A common presentation of inherited prion disease is Gerstmann-Sträussler-Scheinker syndrome, typically presenting with gait ataxia and painful dysaesthesiae in the legs evolving over 2–5 years. The most frequent molecular genetic diagnosis is a P102L mutation of the prion protein gene (PRNP). There is no explanation for why this clinical syndrome is so distinct from Creutzfeldt-Jakob disease, and biomarkers of the early stages of disease have not been developed. Here we aimed, first, at determining if quantitative neurophysiological assessments could predict clinical diagnosis or disability and monitor progression and, second, to determine the neuropathological basis of the initial clinical and neurophysiological findings. We investigated subjects known to carry the P102L mutation in the longitudinal observational UK National Prion Monitoring Cohort study, with serial assessments of clinical features, peripheral nerve conduction, H and F components, threshold tracking and histamine flare and itch response and neuropathological examination in some of those who died. Twenty-three subjects were studied over a period of up to 12 years, including 65 neurophysiological assessments at the same department. Six were symptomatic throughout and six became symptomatic during the study. Neurophysiological abnormalities were restricted to the lower limbs. In symptomatic patients around the time of, or shortly after, symptom onset the H-reflex was lost. Lower limb thermal thresholds were at floor/ceiling in some at presentation, in others thresholds progressively deteriorated. Itch sensation to histamine injection was lost in most symptomatic patients. In six patients with initial assessments in the asymptomatic stage of the disease, a progressive deterioration in the ability to detect warm temperatures in the feet was observed prior to clinical diagnosis and the onset of disability. All of these six patients developed objective abnormalities of either warm or cold sensation prior to the onset of significant symptoms or clinical diagnosis. Autopsy examination in five patients (including two not followed clinically) showed prion protein in the substantia gelatinosa, spinothalamic tracts, posterior columns and nuclei and in the neuropil surrounding anterior horn cells. In conclusion, sensory symptoms and loss of reflexes in Gerstmann-Sträussler-Scheinker syndrome can be explained by neuropathological changes in the spinal cord. We conclude that the sensory symptoms and loss of lower limb reflexes in Gerstmann-Sträussler-Scheinker syndrome is due to pathology in the caudal spinal cord. Neuro-physiological measures become abnormal around the time of symptom onset, prior to diagnosis, and may be of value for improved early diagnosis and for recruitment and monitoring of progression in clinical trials.

Although colocalization of amyloid β (Aβ) with prion protein (PrP) in the kuru plaque has previously been observed in the brain of prion diseases patients, the participating Aβ species has not been identified. Here, we present an immunohistochemical assessment of the brain and spinal cord of a 69-year-old Japanese female patient with Gerstmann-Sträussler-Scheinker disease with a P105L mutation on the PRNP gene (GSS-P105L). Immunohistochemical assessment of serial brain sections was performed using anti-PrP and -Aβ antibodies in the hippocampus, frontal and occipital lobes. She died 69 years after a 21-year clinical course. Immunohistochemistorical examination revealed that ~50% of the kuru plaques in the cerebrum were colocalized with Aβ, and Aβ42 was predominantly observed to be colocalized with PrP-plaques. The Aβ deposition patterns were unique, and distinct from diffuse plaques observed in the normal aging brain or Alzheimer's disease brain. The spinal cord exhibited degeneration in the lateral corticospinal tract, posterior horn, and fasciculus gracilis. We have demonstrated for the first time that Aβ42, rather than Aβ40, is the main Aβ component associated with PrP-plaques, and also the degeneration of the fasciculus gracilis in the spinal cord in GSS-P105L, which could be associated with specific clinical features of GSS-P105L.

This is the first report of presumed sporadic Creutzfeldt-Jakob disease (sCJD) and Gerstmann-Straussler-Scheinker disease (GSS) with the prion protein gene c.305C>T mutation (p.P102L) occurring in one family. The father and son were affected with GSS and the mother had a rapidly progressive form of CJD. Diagnosis of genetic, variant, and iatrogenic CJD was ruled out based on the mother's clinical history, genetic tests, and biochemical investigations, all of which supported the diagnosis of sCJD. However, given the low incidence of sCJD and GSS, their co-occurrence in one family is extraordinary and challenging. Thus, a hypothesis for the transmission of infectious prion proteins (PrPSc) via microchimerism was proposed and investigated. DNA from 15 different brain regions and plasma samples of the CJD patient was subjected to PCR and shallow sequencing for detection of a male sex-determining chromosome Y (chr. Y). However, no trace of chr. Y was found. A long CJD incubation period or presumed small concentrations of chr. Y may explain the obtained results. Further studies of CJD and GSS animal models with controlled genetic and proteomic features are needed to determine whether maternal CJD triggered via microchimerism by a GSS fetus might present a new PrPSc transmission route.

Translational neuroscience integrates the knowledge derived by basic neuroscience with the development of new diagnostic and therapeutic tools that may be applied to clinical practice in neurological diseases. This information can be used to improve clinical trial designs and outcomes that will accelerate drug development, and to discover novel biomarkers which can be efficiently employed to early recognize neurological disorders and provide information regarding the effects of drugs on the underlying disease biology. Alzheimer's disease (AD) and prion disease are two classes of neurodegenerative disorders characterized by incomplete knowledge of the molecular mechanisms underlying their occurrence and the lack of valid biomarkers and effective treatments. For these reasons, the design of therapies that prevent or delay the onset, slow the progression, or improve the symptoms associated to these disorders is urgently needed. During the last few decades, translational research provided a framework for advancing development of new diagnostic devices and promising disease-modifying therapies for patients with prion encephalopathies and AD. In this review, we provide present evidence of how supportive can be the translational approach to the study of dementias and show some results of our preclinical studies which have been translated to the clinical application following the 'bed-to-bench-and-back' research model.

Gerstmann-Sträussler-Scheinker disease (GSS) with the P102L mutation in PRNP gene is characterized with progressive cerebellar dysfunction clinically and PrP(Sc) plaques neurologically. Due to the cerebellar ataxia in the early stage, GSS P102L is often misdiagnosed as other neurodegenerative disorders. We presented here a 49-year-old female patient with proven P102L PRNP mutation, and three heterologous mutations in hereditary ataxias associated gene SYNE1, including p.V3643L, p.M3376V and p.T2860A. The patient appeared progressive unsteady gait in early stage and developed the Creutzfeldt-Jacob disease (CJD) – associated clinical manifestations, including progressive dementia, myoclonus, pyramidal and extrapyramidal signs. She is still alive but with akinetic mutism 21 months after onset. Observation of intense signal changes in cortical regions (cortical ribboning) in diffusion weighted imaging (DWI) MRI scanning and positive protein 14-3-3 in cerebrospinal fluid (CSF) proposed the diagnosis of sporadic CJD. The final diagnosis of P102L GSS was made after PRNP sequencing.

Conformational conversion of the cellular isoform of prion protein, PrPC, into the abnormally folded, amyloidogenic isoform, PrPSc, is an underlying pathogenic mechanism in prion diseases. The diseases manifest as sporadic, hereditary, and acquired disorders. Etiological mechanisms driving the conversion of PrPC into PrPSc are unknown in sporadic prion diseases, while prion infection and specific mutations in the PrP gene are known to cause the conversion of PrPC into PrPSc in acquired and hereditary prion diseases, respectively. We recently reported that a neurotropic strain of influenza A virus (IAV) induced the conversion of PrPC into PrPSc as well as formation of infectious prions in mouse neuroblastoma cells after infection, suggesting the causative role of the neuronal infection of IAV in sporadic prion diseases. Here, we discuss the conversion mechanism of PrPC into PrPSc in different types of prion diseases, by presenting our findings of the IAV infection-induced conversion of PrPC into PrPSc and by reviewing the so far reported transgenic animal models of hereditary prion diseases and the reverse genetic studies, which have revealed the structure-function relationship for PrPC to convert into PrPSc after prion infection.

Gerstmann-Sträussler-Scheinker disease (GSS) is a genetic prion disease. Swallowing function evaluation in patients with GSS remains unclear. Here, we describe a case of videofluoroscopic examination of swallowing (VF) to facilitate continued oral ingestion in a patient with P105L GSS. A 67-year-old woman developed gait disturbance and Parkinsonism symptoms at the age of 54 years. Since her family wanted her to continue oral ingestion, we performed VF, which revealed impairment and preservation of the oral and pharyngeal phases, respectively. Moreover, the impairment of the oral phase was improved by adjusting the patient’s posture and food consistency. A swallowing function evaluation based on the condition of a patient with GSS may facilitate continued oral ingestion.

Familial British dementia (FBD) and familial Danish dementia (FDD) are caused by mutations in the BRI2 gene. These diseases are characterized clinically by progressive dementia and ataxia and neuropathologically by amyloid deposits and neurofibrillary tangles. Herein, we investigate BRI2 protein accumulation in FBD, FDD, Alzheimer disease and Gerstmann-Sträussler-Scheinker disease. In FBD and FDD, we observed reduced processing of the mutant BRI2 pro-protein, which was found accumulating intracellularly in the Golgi of neurons and glial cells. In addition, we observed an accumulation of a mature form of BRI2 protein in dystrophic neurites, surrounding amyloid cores. Accumulation of BRI2 was also observed in dystrophic neurites of Alzheimer disease and Gerstmann-Sträussler-Scheinker disease cases. Although it remains to be determined whether intracellular accumulation of BRI2 may lead to cell damage in these degenerative diseases, our study provides new insights into the role of mutant BRI2 in the pathogenesis of FBD and FDD and implicates BRI2 as a potential indicator of neuritic damage in diseases characterized by cerebral amyloid deposition.

Gerstmann-Straussler-Scheinker disease (GSS) is a rare prion disease characterized by cerebellar ataxia with progressive cognitive decline.

Gerstmann-Sträussler-Scheinker disease (GSS) is characterized by atypical N- and C-terminal cleaved protease-resistant PrPSc. Vanni et al. report that PrPSc oligomers purified from patients with GSS are authentic – but non-fibrillar – prions, thus uncovering the minimal prion protein domain able to encode infectious prions., Prions are transmissible agents causing lethal neurodegenerative diseases that are composed of aggregates of misfolded cellular prion protein (PrPSc). Despite non-fibrillar oligomers having been proposed as the most infectious prion particles, prions purified from diseased brains usually consist of large and fibrillar PrPSc aggregates, whose protease-resistant core (PrPres) encompasses the whole C-terminus of PrP. In contrast, PrPSc from Gerstmann-Sträussler-Scheinker disease associated with alanine to valine substitution at position 117 (GSS-A117V) is characterized by a small protease-resistant core, which is devoid of the C-terminus. We thus aimed to investigate the role of this unusual PrPSc in terms of infectivity, strain characteristics, and structural features. We found, by titration in bank voles, that the infectivity of GSS-A117V is extremely high (109.3 ID50 U/g) and is resistant to treatment with proteinase K (109.0 ID50 U/g). We then purified the proteinase K-resistant GSS-A117V prions and determined the amount of infectivity and PrPres in the different fractions, alongside the morphological characteristics of purified PrPres aggregates by electron microscopy. Purified pellet fractions from GSS-A117V contained the expected N- and C-terminally cleaved 7 kDa PrPres, although the yield of PrPres was low. We found that this low yield depended on the low density/small size of GSS-A117V PrPres, as it was mainly retained in the last supernatant fraction. All fractions were highly infectious, thus confirming the infectious nature of the 7 kDa PrPres, with infectivity levels that directly correlated with the PrPres amount detected. Finally, electron microscopy analysis of these fractions showed no presence of amyloid fibrils, but only very small and indistinct, non-fibrillar PrPresparticles were detected and confirmed to contain PrP via immunogold labelling. Our study demonstrates that purified aggregates of 7 kDa PrPres, spanning residues ∼90–150, are highly infectious oligomers that encode the biochemical and biological strain features of the original sample. Overall, the autocatalytic behaviour of the prion oligomers reveals their role in the propagation of neurodegeneration in patients with Gerstmann-Sträussler-Scheinker disease and implies that the C-terminus of PrPSc is dispensable for infectivity and strain features for this prion strain, uncovering the central PrP domain as the minimal molecular component able to encode infectious prions. These findings are consistent with the hypothesis that non-fibrillar prion particles are highly efficient propagators of disease and provide new molecular and morphological constraints on the structure of infectious prions.

The prion diseases, also known as transmissible spongiform encephalopathies (TSEs), represent a unique family of rare neurodegenerative disorders. They have much in common with other neurodegenerative diseases, but they are distinguished from all others by their highly transmissible nature. In addition, the host range of prion disease (PrD) is unusual in that animals, in addition to humans, can be affected and, as demonstrated by the experience of mad cow disease, prion disease can jump between species. Although the core features of these diseases include progressive dementia, ataxia, and variable neurological and psychiatric symptoms, several clinical and histopathologic phenotypes of disease are recognized. Despite this phenotypic variation, the etiology of all is traced to the misfolded isoform of a single protein known as the prion protein (PrP), a normal constituent of the plasma membrane of cells, especially neurons. There are several fascinating aspects of these diseases, including the origins of its discovery, the nature of its biology, and the future challenges for diagnosis and treatment. From sheep to cannibals to mad cows, the prion diseases have a rich and controversial history. Deciphering the molecular nature of prion generation and propagation will be key to developing a therapeutic approach to these diseases.

In the article “Pearls & Oy-sters: Challenging diagnosis of Gerstmann-Straussler-Scheinker disease: Clinical and imaging findings,” Kang et al. presented the case of a 49-year-old man with progressive ataxia, dysarthria, and cognitive impairment who was found to have a heterozygous mutation in the prion protein (PRNP) gene, suspected to be de novo, resulting in a diagnosis of Gerstmann-Straussler-Scheinker disease (GSS). In the accompanying discussion, they also presented a review of the clinical manifestations, diagnostic test results, and presence of family history of GSS in 86 patients (including theirs). In response, Dr. Paucar notes that the polymorphic PRNP codon 129M has disease-modifying effect on GSS and that real-time quaking-induced conversion (RT-QuIC) can be helpful in patients with suspected prion disease, especially with ambiguous family history, and that a discussion of transmissibility of GSS-associated PRNP mutations would have been helpful. Responding to these comments, Park et al. report the results of PRNP codon 129M polymorphisms in their review and that they found the methionine/valine heterozygote to have slightly earlier disease onset. They note that they could not evaluate the role of RT-QuIC but report that 87.7% of the patients with the P102L mutation (found in their patient) had a positive family history, whereas 8 other single-case mutations had a negative family history. In the article “Pearls & Oy-sters: Challenging diagnosis of Gerstmann-Straussler-Scheinker disease: Clinical and imaging findings,” Kang et al. presented the case of a 49-year-old man with progressive ataxia, dysarthria, and cognitive impairment who was found to have a heterozygous mutation in the prion protein (PRNP) gene, suspected to be de novo, resulting in a diagnosis of Gerstmann-Straussler-Scheinker disease (GSS). In the accompanying discussion, they also presented a review of the clinical manifestations, diagnostic test results, and presence of family history of GSS in 86 patients (including theirs). In response, Dr. Paucar notes that the polymorphic PRNP codon 129M has disease-modifying effect on GSS and that real-time quaking-induced conversion (RT-QuIC) can be helpful in patients with suspected prion disease, especially with ambiguous family history, and that a discussion of transmissibility of GSS-associated PRNP mutations would have been helpful. Responding to these comments, Park et al. report the results of PRNP codon 129M polymorphisms in their review and that they found the methionine/valine heterozygote to have slightly earlier disease onset. They note that they could not evaluate the role of RT-QuIC but report that 87.7% of the patients with the P102L mutation (found in their patient) had a positive family history, whereas 8 other single-case mutations had a negative family history.

Despite their phenotypic heterogeneity, most human prion diseases belong to two broadly defined groups: Creutzfeldt-Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker disease (GSS). While the structural characteristics of the disease-related proteinase K-resistant prion protein (resPrPD) associated with the CJD group are fairly well established, many features of GSS-associated resPrPD are unclear. Electrophoretic profiles of resPrPD associated with GSS variants typically show 6–8 kDa bands corresponding to the internal PrP fragments as well as a variable number of higher molecular weight bands, the molecular nature of which has not been investigated. Here we have performed systematic studies of purified resPrPD species extracted from GSS cases with the A117V (GSSA117V) and F198S (GSSF198S) PrP gene mutations. The combined analysis based on epitope mapping, deglycosylation treatment and direct amino acid sequencing by mass spectrometry provided a conclusive evidence that high molecular weight resPrPD species seen in electrophoretic profiles represent covalently-linked multimers of the internal ~ 7 and ~ 8 kDa fragments. This finding reveals a mechanism of resPrPD aggregate formation that has not been previously established in prion diseases. Electronic supplementary material The online version of this article (10.1186/s40478-019-0734-2) contains supplementary material, which is available to authorized users.

Gerstmann-Straussler-Scheinker syndrome (GSS) with the P102L mutation is a rare genetic prion disease caused by a pathogenic mutation at codon 102 in the prion protein gene. Cluster analysis encompassing data from 7 Czech patients and 87 published cases suggests the existence of 4 clinical phenotypes (typical GSS, GSS with areflexia and paresthesia, pure dementia GSS, and Creutzfeldt-Jakob disease-like GSS); GSS may be more common than previously estimated. In making a clinical diagnosis or progression estimates of GSS, magnetic resonance imaging and real-time quaking-induced conversion may be helpful, but the results should be evaluated with respect to the overall clinical context. ANN NEUROL 2019;86:643-652.

Although it is not yet universally accepted that all neurodegenerative diseases (NDs) are prion disorders, there is little disagreement that Alzheimer’s disease (AD), Parkinson’s disease, frontotemporal dementia (FTD), and other NDs are a consequence of protein misfolding, aggregation, and spread. This widely accepted perspective arose from the prion hypothesis, which resulted from investigations on scrapie, a common transmissible disease of sheep and goats. The prion hypothesis argued that the causative infectious agent of scrapie was a novel proteinaceous pathogen devoid of functional nucleic acids and distinct from viruses, viroids, and bacteria. At the time, it seemed impossible that an infectious agent like the one causing scrapie could replicate and exist as diverse microbiological strains without nucleic acids. However, aggregates of a misfolded host-encoded protein, designated the prion protein (PrP), were shown to be the cause of scrapie as well as Creutzfeldt–Jakob disease (CJD) and Gerstmann–Sträussler–Scheinker syndrome (GSS), which are similar NDs in humans. This review discusses historical research on diseases caused by PrP misfolding, emphasizing principles of pathogenesis that were later found to be core features of other NDs. For example, the discovery that familial prion diseases can be caused by mutations in PrP was important for understanding prion replication and disease susceptibility not only for rare PrP diseases but also for far more common NDs involving other proteins. We compare diseases caused by misfolding and aggregation of APP-derived Aβ peptides, tau, and α-synuclein with PrP prion disorders and argue for the classification of NDs caused by misfolding of these proteins as prion diseases. Deciphering the molecular pathogenesis of NDs as prion-mediated has provided new approaches for finding therapies for these intractable, invariably fatal disorders and has revolutionized the field.

EEG findings in advanced Gerstmann-Sträussler-Scheinker syndrome (GSS) are shown. A 56-year-old woman developed GSS symptoms and was diagnosed as having GSS with the P102L mutation at age 58. During the early stage, there were no significant EEG findings. Her clinical condition worsened and she developed akinetic mutism at age 62. The patient died of pneumonia at age 65. EEGs were recorded annually from age 61 to 65. Bilateral independent periodic discharges (BIPDs) in both temporal areas appeared at age 64. No clinical seizures were noticed. MEG showed the sharp waves of BIPDs originated independently in each temporal lobe. Other causes of BIPDs were absent.

Rationale: Gerstmann-Sträussler-Scheinker syndrome (GSS) is a rare autosomal dominant disease caused by a mutation in the prion protein gene (PRNP) that is not well known among neurologists and is therefore easily misdiagnosed. Patient concerns : A 49-year-old man was admitted for the first time because of an unsteady walk with mogilalia for 1 year. He underwent a cervical discectomy and a plate-screw fixation 6 months prior, although postoperative gait instability did not improve. Diagnosis: Whole exome sequencing identified a pathogenic and heterozygous mutation in the PRNP 4 years after onset. The patient was eventually diagnosed with GSS. Interventions: Symptomatic treatment to improve cerebrocirculation and cerebrometabolism was provided. Outcomes: The neurological decline continued. The Mini-Mental State Examination and modified Rankin Scale scores changed from 19 to 11 and 2 to 5, respectively. Progressive cerebral and cerebellar atrophy on magnetic resonance imaging was observed. Lessons: Cerebral and cerebellar atrophy are neuroimaging features symptomatic of GSS that become more apparent as the disease progresses. This atrophy is positively correlated with the severity of symptoms and reduced quality of life. Neurologists treating middle-aged patients with progressive ataxia, cognitive impairment or dysarthria, and brain atrophy need to consider the possibility of GSS.

Although prion diseases are generally thought to present as rapidly progressive dementias with survival of only a few months, the phenotypic spectrum for genetic prion diseases (gPrDs) is much broader. The majority have a rapid decline with short survival, but many patients with gPrDs present as slowly progressive ataxic or parkinsonian disorders with progression over a few to several years. A few very rare mutations even present as neuropsychiatric disorders, sometimes with systemic symptoms such as gastrointestinal disorders and neuropathy, progressing over years to decades. gPrDs are caused by mutations in the prion protein gene (PRNP), and have been historically classified based on their clinicopathological features as genetic Jakob-Creutzfeldt disease (gJCD), Gerstmann-Sträussler-Scheinker (GSS), or Fatal Familial Insomnia (FFI). Mutations in PRNP can be missense, nonsense, and octapeptide repeat insertions or a deletion, and present with diverse clinical features, sensitivities of ancillary testing, and neuropathological findings. We present the UCSF gPrD cohort, including 129 symptomatic patients referred to and/or seen at UCSF between 2001 and 2016, and compare the clinical features of the gPrDs from 22 mutations identified in our cohort with data from the literature, as well as perform a literature review on most other mutations not represented in our cohort. E200K is the most common mutation worldwide, is associated with gJCD, and was the most common in the UCSF cohort. Among the GSS-associated mutations, P102L is the most commonly reported and was also the most common at UCSF. We also had several octapeptide repeat insertions (OPRI), a rare nonsense mutation (Q160X), and three novel mutations (K194E, E200G, and A224V) in our UCSF cohort. © 2016 Wiley Periodicals, Inc.

Prion diseases, or transmissible spongiform encephalopathies, have revealed the bewildering phenomenon of transmissibility in neurodegenerative diseases. Hence, the experimental transmissibility of prion-like neurodegenerative diseases via template directed misfolding has become the focus of intense research. Gerstmann-Sträussler-Scheinker disease (GSS) is an inherited prion disease associated with mutations in the prion protein gene. However, with the exception of a few GSS cases with P102L mutation characterized by co-accumulation of protease-resistant PrP core (PrPres) of ∼21 kDa, attempts to transmit to rodents GSS associated to atypical misfolded prion protein with ∼8 kDa PrPres have been unsuccessful. As a result, these GSS subtypes have often been considered as non-transmissible proteinopathies rather than true prion diseases. In a recent study we inoculated bank voles with GSS cases associated with P102L, A117V and F198S mutations and found that they transmitted efficiently and produced distinct pathological phenotypes, irrespective of the presence of 21 kDa PrPres in the inoculum. This study demonstrates that GSS is a genuine prion disease characterized by both transmissibility and strain variation. We discuss the implications of these findings for the understanding of the heterogeneous clinic-pathological phenotypes of GSS and of the molecular underpinnings of prion infectivity.

Blood has been shown to contain disease-associated misfolded prion protein (PrP(TSE)) in animals naturally and experimentally infected with various transmissible spongiform encephalopathy (TSE) agents, and in humans infected with variant Creutzfeldt-Jakob disease (vCJD). Recently, we have demonstrated PrP(TSE) in extracellular vesicle preparations (EVs) containing exosomes from plasma of mice infected with mouse-adapted vCJD by Protein Misfolding Cyclic Amplification (PMCA). Here we report the detection of PrP(TSE) by PMCA in EVs from plasma of mice infected with Fukuoka-1 (FU), an isolate from a Gerstmann-Sträussler-Scheinker disease patient. We used Tga20 transgenic mice that over-express mouse cellular prion protein, to assay by intracranial injections the level of infectivity in a FU-infected brain homogenate from wild-type mice (FU-BH), and in blood cellular components (BCC), consisting of red blood cells, white blood cells and platelets, plasma EVs, and plasma EVs subjected to multiple rounds of PMCA. Only FU-BH and plasma EVs from FU-infected mice subjected to PMCA that contained PrP(TSE) transmitted disease to Tga20 mice. Plasma EVs not subjected to PMCA and BCC from FU-infected mice failed to transmit disease. These findings confirm the high sensitivity of PMCA for PrP(TSE) detection in plasma EVs and the efficiency of this in vitro method to produce highly infectious prions. The results of our study encourage further research to define the role of EVs and, more specifically exosomes, as blood-borne carriers of PrP(TSE).

Prion diseases are transmissible and incurable neurodegenerative disorders of humans and animals. Similar to other neurodegenerative disorders, such as Alzheimer’s disease and Parkinson’s disease, prion diseases are characterized by protein aggregation in the central nervous system (CNS). The key molecular event in prion disease is the conformational conversion of the cellular prion protein, PrPC, into a misfolded and aggregated conformer, PrPSc, which templates further PrPC misfolding [1]. Although this same protein misfolding event occurs in all prion diseases, affected individuals expressing identical PrPC sequences can exhibit strikingly heterogeneous clinical and pathological phenotypes. These phenotypic differences have been linked to distinct PrPSc conformations, known as strains, yet the source of prion strain diversity is incompletely understood. One potential contributor to strain diversity lies in the posttranslational modifications (PTMs) on PrPC, which add a layer of structural complexity to an otherwise highly conserved protein. PrPC is posttranslationally modified by the covalent linkage of (i) 0 to 2 N-linked glycans at positions 181 and 197 (human PrP) and (ii) a glycosylphosphatidylinositol (GPI) moiety, which anchors PrPC in the outer leaflet of the plasma membrane [2,3]. The N-linked glycans on PrPC are branched [bi- (51%), tri- (32%), or tetra-antennary (17%)] and terminally sialylated, predominantly via alpha 2,6 linkages [4–6]. While necessary for regulating protein interactions and function, PTMs can profoundly modulate the pathogenesis of neurodegenerative diseases. For example, aberrant hyperphosphorylation of tau protein leads to tau detachment from microtubules and fibrillization into neurofibrillary tangles, a pathologic hallmark of Alzheimer’s disease. Prion diseases are no different, and the presence of PrP PTMs can markedly alter both the disease phenotype and transmission barrier. Here we explore how PrP PTMs impact prion conversion, cross-species transmission, the neuroinflammatory response, and PrP interaction with cofactors.

Fatal familial insomnia (FFI), genetic Creutzfeldt–Jakob disease (gCJD), and Gerstmann–Sträussler–Scheinker (GSS) syndrome are neurodegenerative disorders linked to prion protein (PrP) mutations. The pathogenic mechanisms are not known, but increasing evidence points to mutant PrP misfolding and retention in the secretory pathway. We previously found that the D178N/M129 mutation associated with FFI accumulates in the Golgi of neuronal cells, impairing post-Golgi trafficking. In this study we further characterized the trafficking defect induced by the FFI mutation and tested the 178N/V129 variant linked to gCJD and a nine-octapeptide repeat insertion associated with GSS. We used transfected HeLa cells, embryonic fibroblasts and primary neurons from transgenic mice, and fibroblasts from carriers of the FFI mutation. In all these cell types, the mutant PrPs showed abnormal intracellular localizations, accumulating in the endoplasmic reticulum (ER) and Golgi. To test the efficiency of the membrane trafficking system, we monitored the intracellular transport of the temperature-sensitive vesicular stomatite virus glycoprotein (VSV-G), a well-established cargo reporter, and of endogenous procollagen I (PC-I). We observed marked alterations in secretory trafficking, with VSV-G accumulating mainly in the Golgi complex and PC-I in the ER and Golgi. A redacted version of mutant PrP with reduced propensity to misfold did not impair VSV-G trafficking, nor did artificial ER or Golgi retention of wild-type PrP; this indicates that both misfolding and intracellular retention were required to induce the transport defect. Pharmacological activation of Src family kinase (SFK) improved intracellular transport, suggesting that mutant PrP impairs secretory trafficking through corruption of SFK-mediated signaling.

Background For surveillance projects to be successful, it is important to accurately diagnose all patients, without overlooking any cases. Here, we investigated the present clinical diagnostic accuracy for prion diseases in Japan. Methods We analyzed volumes of the “Annual of the Pathological Autopsy Cases in Japan”, which reported details on 130,105 autopsies conducted from 2007 to 2016 throughout Japan. Results The clinical diagnosis of patients with prion disease had a specificity of 91.3% and a sensitivity of 96.3%. The autopsy rates were estimated as 17.8% for patients with clinically suspected prion disease and as 1.8% for the entire population. Conclusions Despite the good accuracy of clinical diagnoses of prion diseases, a calculated 78.4 patients with prion disease were expected to have gone undiagnosed during the 10-year study period. However, autopsy is estimated to reveal a maximum of only 13.8 of these clinically undiagnosed patients because of the low autopsy rate. The overall autopsy rate, irrespective of any specific disorder, must increase for effective surveillance projects of disease incidence to be conducted.

The p.D202N mutation in PRNP is a rare variant associated with Gerstmann-Straussler-Scheinker disease (GSS), a genetic form of prion cerebral amyloidosis. To date, there have been only 4 reports of this mutation worldwide and only one detailed clinical study (table e-1, [links.lww.com/NXG/A223][1]).1–4 Here, we describe the clinical phenotype and the results of neuroradiologic and laboratory investigations in an Italian patient carrying this genetic variant. [1]: http://links.lww.com/NXG/A223

Prion diseases are neurodegenerative disorders caused by the misfolding of the cellular prion protein (PrPC). Gerstmann-Straussler-Scheinker syndrome is an inherited prion disease with one early-onset allele (HRdup) containing an eight-amino-acid insertion; this LGGLGGYV insert is positioned after valine 129 (human PrPC sequence) in a hydrophobic tract in the natively disordered region. Here we have characterized the structure and explored the molecular motions and dynamics of HRdup PrP and a control allele. High-resolution NMR data suggest that the core of HRdup has a canonical PrPC structure, yet a nascent β-structure is observed in the flexible elongated hydrophobic region of HRdup. In addition, using mouse PrPC sequence, we observed that a methionine/valine polymorphism at codon 128 (equivalent of methionine/valine 129 in human sequence) and oligomerization caused by high protein concentration affects conformational exchange dynamics at residue G130. We hypothesize that with the β-structure at the N-terminus, the hydrophobic region of HRdup can adopt a fully extended configuration and fold back to form an extended β-sheet with the existing β-sheet. We propose that these structures are early chemical events in disease pathogenesis.

Abnormal prion proteins are responsible for several fatal neurodegenerative diseases in humans and in animals, including Creutzfeldt–Jakob disease (CJD), Gerstmann–Sträussler–Scheinker disease, and fatal familial insomnia. Genetics is important in prion diseases, but in the most cases, cause of diseases remained unknown. Several mutations were found to be causative for prion disorders, and the effect of mutations may be heterogeneous. In addition, different prion mutations were suggested to play a possible role in additional phenotypes, such as Alzheimer’s type pathology, spongiform encephalopathy, or frontotemporal dementia. Pathogenic nature of several prion mutations remained unclear, such as M129V and E219K. These two polymorphic sites were suggested as either risk factors for different disorders, such as Alzheimer’s disease (AD), variant CJD, or protease-sensitive prionopathy, and they can also be disease-modifying factors. Pathological overlap may also be possible with AD or progressive dementia, and several patients with prion mutations were initially diagnosed with AD. This review also introduces briefly the diagnosis of prion diseases and the issues with their diagnosis. Since prion diseases have quite heterogeneous phenotypes, a complex analysis, a combination of genetic screening, cerebrospinal fluid biomarker analysis and imaging technologies could improve the early disease diagnosis.

To address the question of cross-talk between prion protein (PrP) and Alzheimer’s disease (AD), we generated TgAD/GSS mice that develop amyloid-β (Aβ) plaques of AD and PrP (specifically mutated PrPA116V) plaques of Gerstmann-Sträussler-Scheinker disease (GSS) and compared plaque-related features in these mice to AD mice that express normal (TgAD), high (TgAD/HuPrP), or no (TgAD/PrP−/−) PrPC. In contrast to PrPC, PrPA116V weakly co-localized to Aβ plaques, did not co-immunoprecipitate with Aβ, and poorly bound to Aβ in an ELISA-based binding assay. Despite the reduced association of PrPA116V with Aβ, TgAD/GSS and TgAD/HuPrP mice that express comparable levels of PrPA116V and PrPC respectively, displayed similar increases in Aβ plaque burden and steady state levels of Aβ and its precursor APP compared with TgAD mice. Our Tg mouse lines also revealed a predominance of intracellular Aβ plaques in mice lacking PrPC (TgAD/PrP−/−, TgAD/GSS) compared with an extracellular predominance in PrPC-expressing mice (TgAD, TgAD/HuPrP). Parallel studies in N2aAPPswe cells revealed a direct dependence on PrPC but not PrPA116V for exosome-related secretion of Aβ. Overall, our findings are two-fold; they suggest that PrP expression augments Aβ plaque production, at least in part by an indirect mechanism, perhaps by increasing steady state levels of APP, while they also provide support for a fundamental role of PrPC to bind to and deliver intraneuronal Aβ to exosomes for secretion.

Among genetically determined neurodegenerative diseases, the dominantly inherited prion protein cerebral amyloidoses are characterized by deposition of amyloid in cerebral parenchyma or blood vessels. Among them, Gerstmann-Sträussler-Scheinker disease has been the first to be described. Their clinical, neuropathologic, and molecular phenotypes are distinct from those observed in Creutzfeldt-Jakob disease (CJD) and related spongiform encephalopathies. It is not understood why specific mutations in the prion protein gene (PRNP) cause cerebral amyloidosis and others cause CJD. A significant neurobiologic event in these amyloidoses is the frequent coexistence of prion amyloid with tau neurofibrillary pathology, a phenomenon suggesting that similar pathogenetic mechanisms may be shared among different diseases in the sequence of events occurring in the cascade from amyloid formation to tau aggregation. This chapter describes the clinical, neuropathologic, and biochemical phenotypes associated with each of the PRNP mutations causing an inherited cerebral amyloidosis and emphasizes the variability of phenotypes.

Our previous studies showed that intravenous immunoglobulin (IVIG) contained anti-Aβ autoantibodies that might be able to treat Alzheimer’s disease (AD). Recently, we identified and characterized naturally occurring autoantibodies against PrP from IVIG. Although autoantibodies in IVIG blocked PrP fibril formation and PrP neurotoxicity in vitro, it remained unknown whether IVIG could reduce amyloid plaque pathology in vivo and be used to effectively treat animals with prion diseases. In this study, we used Gerstmann-Straussler-Scheinker (GSS)-Tg (PrP-A116V) transgenic mice to test IVIG efficacy since amyloid plaque formation played an important role in GSS pathogenesis. Here, we provided strong evidence that demonstrates how IVIG could significantly delay disease onset, elongate survival, and improve clinical phenotype in Tg (PrP-A116V) mice. Additionally, in treated animals, IVIG could markedly inhibit PrP amyloid plaque formation and attenuate neuronal apoptosis at the age of 120 days in mice. Our results indicate that IVIG may be a potential, effective therapeutic treatment for GSS and other prion diseases.

iWe report here autophagy in the optic nerve in experimental Gerstmann-Sträussler-Scheinker disease (GSS) (Fujisaki-1) in mice and experimental Creutzfeldt-Jakob disease (CJD) (Echigo-1) in hamsters. Lesions of both experimental GSS in mice and experimental CJD in hamsters were practically indistinguishable. Briefly, they consisted of widespread Wallerian degeneration, spongiform change and a glial reaction. Numerous axonal swellings were seen. The latter were filled with numerous mitochondria and lysosomal electron-dense bodies. Autophagic vacuoles defined as structures bound in double membranes were readily found in many neuronal processes. The following description is organized as a sequence; however, the changes were all observed in the same specimens. First several empty double membrane-bound autophagic vacuoles were seen. In several of those vacuoles, the inner membrane was separated from the outer membrane and enclosed cargo. At the final stage, a mixture of empty autophagic vacuoles and electron-dense lysosomal vesicles was seen. Dystrophic neurites filled with a mixture of mitochondria, empty autophagic vacuoles and electron-dense lysosomal vesicles were interpreted as the final stage of autophagy. Of note, several areas were replaced with dense astrocytic gliosis./i.

Gerstmann-Sträussler-Scheinker (GSS) syndrome is a fatal autosomal dominant neurodegenerative prionopathy clinically characterized by ataxia, spastic paraparesis, extrapyramidal signs and dementia. In some GSS familiar cases carrying point mutations in the PRNP gene, patients also showed comorbid tauopathy leading to mixed pathologies. In this study we developed an induced pluripotent stem (iPS) cell model derived from fibroblasts of a GSS patient harboring the Y218N PRNP mutation, as well as an age-matched healthy control. This particular PRNP mutation is unique with very few described cases. One of the cases presented neurofibrillary degeneration with relevant Tau hyperphosphorylation. Y218N iPS-derived cultures showed relevant astrogliosis, increased phospho-Tau, altered microtubule-associated transport and cell death. However, they failed to generate proteinase K-resistant prion. In this study we set out to test, for the first time, whether iPS cell-derived neurons could be used to investigate the appearance of disease-related phenotypes (i.e, tauopathy) identified in the GSS patient., SCOPUS: ar.j, info:eu-repo/semantics/published

Background and purpose Gerstmann-Straussler-Scheinker syndrome is a rare hereditary neurodegenerative disorder with clinical heterogeneity. This study is aim to demonstrate the clinical spectrum and radiologic characteristics of patients caused by Pro102Leu mutation in PRNP. Materials and methods We retrospect clinical manifestations of five patients from four Japanese families, and comprehensively analyzed their brain MRI, SPECT (N-isopropyl-p-[123I] iodoamphetamine), and PET (18F-2-fluoro-2-deoxy- d -glucose) images. Results All patients developed ataxia of lower limbs and trunk, gait disturbance, dysesthesia in legs, and lower limb hyporeflexia. In the early clinical stage before dementia began, no noticeable abnormalities could be observed from brain MRI, but SPECT and PET revealed mosaic-like pattern of blood flow and glucose metabolism of the brain. Predominant abnormalities were found in the occipital and frontal lobes on SPECT and PET analysis, respectively. In SPECT analysis, blood flow of the anterior cerebellar lobes was lower than that of the posterior cerebellar lobes. Conclusions Clinical symptoms resulting from failure of dorsal horn of spinal cord and spinocerebellar tracts were observed in all cases. Radiologic findings revealed individual differences of involved region in their brain, which could produce clinical diversity. We identified a downtrend of blood flow in the anterior cerebellar lobes, a projection field of the spinocerebellar tracts, which is an important feature of Gerstmann-Straussler-Scheinker syndrome.