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Recently, the problem of neurodegenerative diseases in the medical community has become increasingly relevant. This is due to many factors: from insufficiently studied mechanisms of development of some nosological units to low awareness of medical workers. Among neurodegenerative diseases in humans, prions constitute a very specific group, which are infectious protein particles with a unique morphological structure and capable of causing a number of incurable diseases. Despite years of research, no optimal remedy has yet been found to treat them. This review examines the already studied aspects of prion diseases as a class, including small historical background, features of ethiology, pathogenesis, course and outcome of the most common of them, as well as existing research on experimental methods of diagnostics, treatment and prevention of prion infections.

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Gerstmann-Sträussler-Scheinker is a genetic prion disease and the most common mutation is p.Pro102Leu. We report clinical, molecular and neuropathological data of seven individuals, belonging to two unrelated Brazilian kindreds, carrying the p.Pro102Leu. Marked differences among patients were observed regarding age at onset, disease duration and clinical presentation. In the first kindred, two patients had rapidly progressive dementia and three exhibited predominantly ataxic phenotypes with variable ages of onset and disease duration. In this family, age at disease onset in the mother and daughter differed by 39 years. In the second kindred, different phenotypes were also reported and earlier ages of onset were associated with 129 heterozygosis. No differences were associated with apoE genotype. In these kindreds, the codon 129 polymorphism could not explain the clinical variability and 129 heterozygosis was associated with earlier disease onset. Neuropathological examination in two patients confirmed the presence of typical plaques and PrPsc immunopositivity.

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ABSTRACT Gerstmann-Sträussler-Scheinker is a genetic prion disease and the most common mutation is p.Pro102Leu. We report clinical, molecular and neuropathological data of seven individuals, belonging to two unrelated Brazilian kindreds, carrying the p.Pro102Leu. Marked differences among patients were observed regarding age at onset, disease duration and clinical presentation. In the first kindred, two patients had rapidly progressive dementia and three exhibited predominantly ataxic phenotypes with variable ages of onset and disease duration. In this family, age at disease onset in the mother and daughter differed by 39 years. In the second kindred, different phenotypes were also reported and earlier ages of onset were associated with 129 heterozygosis. No differences were associated with apoE genotype. In these kindreds, the codon 129 polymorphism could not explain the clinical variability and 129 heterozygosis was associated with earlier disease onset. Neuropathological examination in two patients confirmed the presence of typical plaques and PrPsc immunopositivity.

RESUMO A doença de Gerstmann-Sträussler-Scheinker é uma doença priônica genética, cuja mutação mais frequente é p.Pro102Leu. Descrevem-se dados clínicos, moleculares e neuropatológicos de sete indivíduos em duas famílias não relacionadas com p.Pro102Leu. Diferenças notáveis entre os pacientes em relação à idade de início, duração da doença e apresentação clínica foram encontradas. Na primeira família, dois pacientes apresentaram demência rapidamente progressiva e três apresentaram fenótipo de ataxia com idade variáveis de início e duração da doença. Nesta família, a idade de início entre mãe e filha diferiu em 39 anos. Na segunda família, fenótipos diferentes foram observados e idades precoces de início dos sintomas foram associadas à heterozigose no códon 129. Não houve diferença em relação ao genótipo do gene da apoE. O genótipo do códon 129 não foi responsável pela variabilidade clínica; heterozigose no códon 129 esteve associada ao início precoce da doença. O exame neuropatológico em dois pacientes confirmou presença de placas típicas e imunohistoquímica para PrPsc.

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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.

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Gerstmann-Sträussler-Scheinker syndrome (GSS) is a dominantly inherited disorder belonging to the group of transmissible human spongiform encephalopathies or prion diseases. Several families affected by GSS with patients carrying mutations in the prion protein gene have been described worldwide. We report clinical, genealogical, neuropathology and molecular study results from two members of the first Argentine kindred affected by GSS. Both family members presented a frontotemporal-like syndrome, one with and the other without ataxia, with different lesions on neuropathology. A Pro to Leu point mutation at codon 102 (P102L) of the prion protein gene was detected in one of the subjects studied. The pathogenic basis of phenotypic variability observed in this family remains unclear, but resembles that observed in other P102L GSS patients from the same family.

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Prion diseases are caused by an abnormal form of the prion protein (PrP(Sc)). We identified, with lectins, post-translational modifications of brain proteins due to glycosylation in a Gerstmann-Sträussler-Scheinker (GSS) patient. The lectin Amaranthus leucocarpus (ALL), specific for mucin type O-glycosylated structures (Galß1,3 GalNAcα1,0 Ser/Thr or GalNAcα1,0 Ser/Thr), and Sambucus nigra agglutinin (SNA), specific for Neu5Acα2,6 Gal/GalNAc, showed positive labeling in all the prion deposits and in the core of the PrP(Sc) deposits, respectively, indicating specific distribution of O-glycosylated and sialylated structures. Lectins from Maackia amurensis (MAA, Neu5Acα2,3), Macrobrachium rosenbergii (MrL, Neu5,9Ac2-specific) and Arachis hypogaea (PNA, Gal-specific) showed low staining of prion deposits. Immunohistochemistry colocalization with prion antibody indicated that all lectins stained prion protein deposits. These results show that specific modifications in the glycosylation pattern are closely related to the hallmark lesions and might be an early event in neuronal degeneration in GSS disease.

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Las enfermedades priónicas son procesos neurodegenerativos producidos por el metabolismo aberrante de una proteína priónica, que afectan a seres humanos y animales durante un período de incubación prolongado, con carácter transmisible y evolución clínica fatal. Entre sus manifestaciones clínicas sobresalen: demencia, ataxia, insomnio, paraplejías, parestesias y conductas anormales. El principal hallazgo anatomopatológico es el aspecto espongiforme del cerebro de animales y personas infectados, causado por la acumulación de las proteínas priónicas en las neuronas, donde forman placas amiloides. No hay tratamiento que cure, mejore o controle los síntomas y signos de estas afecciones, por lo cual existen al respecto numerosas interrogantes y opiniones controvertidas en la comunidad científica mundial; razones todas que justificaron continuar polemizando en este artículo.

Prion diseases are neurodegenerative processes occurred by aberrant metabolism of a prion protein that affect humans and animals during a long period of incubation, with transmissible character and fatal clinical course. Among their clinical manifestations are insanity, ataxia, insomnia, and paraplegias, paresthesias and abnormal behaviors. The main patological finding is the spongiform aspect of the infected animal and human brain caused by accumulation of prion proteins in the neurons, where they form amyloid plaques. There is not treatment that cures, improves or controls symptoms and signs of these conditions, therefore several questions and different opinions in this regard raise in the world scientific community that justified to continue arguing in this paper.

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Las enfermedades prion son un grupo se desordenes degenerativos del sistema nervioso central que comparten características patológicas crónicas y progresivas. Los agentes causales son un grupo de proteínas infectantes sin presencia de ácidos nucleicos. El objetivo de realizar esta revisión es dar a conocer: qué son las enfermedades priónicas, además de aportar datos sobre su fisiopatología, clasificación, modos de transmisión a si como cuadro clínico, diagnóstico y posible tratamiento para lograr una mayor comprensión de estas patologías. Normalmente en nuestro organismo existen proteínas llamadas proteínas priónicas (PrP) las mismas que poseen un nivel de estructuración de tipo hélice alfa que es susceptible a la lisis por proteasas; la patogénesis de estas proteínas se producen cuando aparece una mutación o un cambio conformacional inducido por PrP patógena de otro individuo lo cual altera su estructura tridimensional haciendo imposible su lisis enzimática y su consecuente acumulación en los tejidos afectados, originando así las enfermedades priónicas.

The prion diseases are a group of degenerative disorders of the central nervous system that have chronic and progressive pathological characteristics in common. These diseases are caused by infectious agents called prion. A prion is a small proteinaceous infectious particle which resists inactivation by procedures that modify nucleic acids. The objective of this article is to understand the different aspects of these diseases and to contribute data about its physiopathology, classification, clinical signs and symptoms, diagnosis and treatment to. There exists a cellular protein known as cellular prion protein PrP that have alpha helix structure susceptible to lysis by protease. The pathogenesis of these proteins are produced when the mutation causes a change in the folding pattern of these protein which makes it resistant to the action of proteases and causes it to precipitate as insoluble amyloid. It accumulates in the affected tissue and causes the disease.

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