768 resultados para X-Linked Intellectual Disability


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Relative cognitive impairments are common along the schizophrenia spectrum reflecting potential psychopathological markers. Yet stress, a vulnerability marker in schizophrenia (including its spectrum), is likewise related to cognitive impairments. We investigated whether one such cognitive marker (attenuated functional hemispheric asymmetry) during stressful life periods might be linked to individuals' schizotypal features or rather to individuals' stress-related experiences and behaviours. A total of 58 students performed a left hemisphere dominant (lateralised lexical decisions) and right hemisphere dominant (sex decisions on composite faces) task. In order to account for individual differences in stress sensitivity we separated participants into groups of high or low cognitive reserve according to their average current marks. In addition, participants filled in questionnaires on schizotypy (short O-LIFE), perceived stress, stress response, and a newly adapted questionnaire that enquired about potential stress compensation behaviour (elevated substance use). The most important finding was that enhanced substance use and cognitive disorganisation contributed to a right and left hemisphere shift in language dominance, respectively. We discuss that (i) former reports on right hemisphere shifts in language dominance with positive schizotypy might be explained by an associated higher substance use and (ii) cognitive disorganisation relates to unstable cognitive functioning that depend on individuals' life circumstances, contributing to published reports on inconsistent laterality-schizotypy relationships.

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Purpose: We report an unusual appearance of fundus autofluorescence (FAF) associated with NR2E3-p.G56R-linked autosomal dominant retinitis pigmentosa (ADRP).Methods: Patients were enrolled among three generations in a Swiss family. Molecular diagnosis identified a c.166G>A (p.G56R) mutation. Ophthalmic examination included fundus photography, FAF, near-infrared autofluorescence (NIA), optical coherence tomography (OCT) and visual fields (VF).Results: Fundus examination revealed a wide range of features from unremarkable to attenuated arterial caliber, clumped and spicular pigment deposits in the mid-periphery and optic nerve pallor. FAF showed a double concentric hyperautofluorescent ring: an inner perimacular ring which tended to be smaller in older patients, and an outer ring located along the vascular arcades, which appeared to extend over time towards the periphery and eventually became hypoautofluorescent. The inner and outer hyperautofluorescent rings were seen both on NIA and FAF at a similar localization. There was also a spatial correspondence between the loss of photoreceptor inner segment and outer segment junction on OCT and the area delimited by both double FAF and NIA rings. VF showed either midperipheral annular scotoma or constricted visual field loss in advanced cases, correlating with dystrophic non-functional retinal regions demarcated by the hyperautofluorescent annuli. A double ring of hyperautofluorescence was observed in all but one patient of two additional families, but not in patients harboring mutations in other ADRP genes, including PRPF3, RHO, RP1, PRPH2, PROM1 and CTRP5.Conclusions: The presence of a double concentric hyperautofluorescent ring of FAF may represent a highly penetrant early phenotypic marker of NR2E3-p.G56R-linked ADRP.

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Abstract Sexual selection theory posits that ornaments can signal the genetic quality of an individual. Eumelanin-based coloration is such an ornament and can signal the ability to cope with a physiological stress response because the melanocortin system regulates eumelanogenesis as well as physiological stress responses. In the present article, we experimentally investigated whether the stronger stress sensitivity of light than dark eumelanic individuals stems from differential regulation of stress hormones. Our study shows that darker eumelanic barn owl nestlings have a lower corticosterone release after a stressful event, an association, which was also inherited from the mother (but not the father) to the offspring. Additionally, nestlings sired by darker eumelanic mothers more quickly reduced experimentally elevated corticosterone levels. This provides a solution as to how ornamented individuals can be more resistant to various sources of stress than drab conspecifics. Our study suggests that eumelanin-based coloration can be a sexually selected signal of resistance to stressful events.

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Mutations in the BIGH3 gene on chromosome 5q31 cause four distinct autosomal dominant diseases of the human cornea: granular (Groenouw type I), Reis-Bücklers, lattice type I, and Avellino corneal dystrophies. All four diseases are characterized by both progressive accumulation of corneal deposits and eventual loss of vision. We have identified a specific recurrent missense mutation for each type of dystrophy, in 10 independently ascertained families. Genotype analysis with microsatellite markers surrounding the BIGH3 locus was performed in these 10 families and in 5 families reported previously. The affected haplotype could be determined in 10 of the 15 families and was different in each family. These data indicate that R555W, R124C, and R124H mutations occurred independently in several ethnic groups and that these mutations do not reflect a putative founder effect. Furthermore, this study confirms the specific importance of the R124 and R555 amino acids in the pathogenesis of autosomal dominant corneal dystrophies linked to 5q.

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PURPOSE: Recently, the authors identified a gene, BIGH3, in which different mutations cause a group of hereditary corneal dystrophies: lattice type I and IIIA (CDLI and CDLIIIA), granular Groenouw type I (CDGGI), Avellino (CDA), and Reis-Bücklers' (CDRB). All these disorders are characterized by the progressive accumulation of corneal deposits with different structural organization. Experiments were conducted to determine the role of kerato-epithelin (KE), the product of BIGH3, in the pathogenesis of the diseases. METHODS: KE-15 and KE-2, two rabbit antisera raised against peptides from the 69-364 and 426 - 682 amino acid regions of KE respectively, were used for immunohistology of the corneas obtained after keratoplasty in six CDLI patients, three CDGGI patients, and one CDA patient. RESULTS: The nonamyloid deposits observed in CDGGI stained intensively with KE-15 and KE-2, whereas the amyloid deposits in all analyzed CDLI corneas reacted to KE-2 but not to KE-15. In the CDA cornea, where amyloid and nonamyloid inclusions were present, positive staining with both antisera was observed. CONCLUSIONS: Pathologic amyloid and nonamyloid deposits observed in CDLI, CDGGI-, and CDA-affected corneas are caused by KE accumulation. Different staining patterns of amyloid and nonamyloid deposits observed with antibodies against the amino and carboxyl termini of KE suggest that two mechanisms of KE misfolding are implicated in the pathogenesis of 5q31-linked corneal dystrophies.

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Purpose: To date, the genotype/phenotype correlation of p.G56R-linked autosomal dominant retinitis pigmentosa (ADRP) is limited to less than 10 kindred. The purpose of this study is to report an unusual appearance of fundus autofluorescence (AF) with NR2E3 p.G56R-linked ADRP in a single kindred.Methods: Patients were enrolled among three generations in a previously unreported family. Molecular diagnosis was performed on all exons of NR2E3 and a p.G56R mutation was identified in affected family members only. Examinations included fundus photography, visual fields, optical coherence tomography, AF, near-infrared AF and ISCEV-standard electrophysiology (ERG).Results: Among 10 examined family members, 5 were affected. The youngest and oldest patients were 16 and 65 years old, respectively. Fundus examination revealed a range of retinal disorder from normal to optic nerve pallor, attenuated arterial caliber and bone spicule-like pigment deposits. In all patients, AF showed a double hyperfluorescent ring; an inner paramacular ring which extension was comparable among patients and an outer ring along the vascular arcades which extended towards periphery in older patients and became hypofluorescent. Maximal scotopic ERGs when recordable showed an increased a/b wave ratio.Conclusions: A double hyperfluorescent ring on AF is an uncommon observation and might be a specific clinical finding in NR2E3 p.G56R-linked ADRP. The consistency of that finding in all affected members of our 3-generation family confirms a previous study. Further analysis is required to determine whether AF changes are associated with particular retinal layer abnormalities.

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BACKGROUND: Fragile X-associated tremor/ataxia syndrome (FXTAS) is an inherited late-onset neurodegenerative disorder, characterized both by neurological and cognitive deficits. It is caused by the expansion of CGG repeats (55 to 200 repeats) in the noncoding region of the fragile X mental retardation 1 (FMR1) gene. Abnormal immunological patterns are often associated with neurodegenerative disorders and implicated in their etiology. We therefore investigated the immune status of FXTAS patients, which had not been assessed prior to this study. METHOD: Peripheral blood mononuclear cells (PBMCs) were collected from 15 asymptomatic FMR1 premutation carriers and 20 age-matched controls. Concentrations of three cytokines (IL-6, IL-8, IL-10) were measured in PBMC supernatants using ELISA assays. RESULTS: We found a significant increase in the concentration of the major anti-inflammatory cytokine IL-10 in supernatants of PBMCs derived from premutation carriers, when compared with controls (P = 0.019). This increase correlated significantly with the number of CGG repeats (P = 0.002). CONCLUSIONS: Elevated IL-10 levels were observed in all premutation carriers, before appearance of the classical neurological symptoms; therefore, IL-10 may be one of the early biomarkers of FXTAS.

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ABSTRACT: Excitotoxicity and cerebral ischemia induce strong endocytosis in neurons, and we here investigate its functional role in neuroprotection by a functional transactivator of transcription (TAT)-peptide, the c-Jun N-terminal kinase (JNK) inhibitor D-JNKI1, against NMDA-excitotoxicity in vitro and neonatal ischemic stroke in P12 Sprague-Dawley rats. In both situations, the neuroprotective efficacy of D-JNKI1 was confirmed, but excessively high doses were counterproductive. Importantly, the induced endocytosis was necessary for neuroprotection, which required that the TAT-peptide be administered at a time when induced endocytosis was occurring. Uptake by other routes failed to protect, and even promoted cell death at high doses. Blocking the induced endocytosis of D-JNKI1 with heparin or with an excess of D-TAT-peptide eliminated the neuroprotection. We conclude that excitotoxicity-induced endocytosis is a basic property of stressed neurons that can target neuroprotective TAT-peptides into the neurons that need protection. Furthermore, it is the main mediator of neuroprotection by D-JNKI1. This may explain promising reports of strong neuroprotection by TAT-peptides without apparent side effects, and warns that the timing of peptide administration is crucial.

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In sharp contrast to birds and mammals, most cold-blooded vertebrates have homomorphic (morphologically undifferentiated) sex chromosomes. This might result either from recurrent X-Y recombination (occurring e.g. during occasional events of sex reversal) or from frequent turnovers (during which sex-determining genes are overthrown by new autosomal mutations). Evidence for turnovers is indeed mounting in fish, but very few have so far been documented in amphibians, possibly because of practical difficulties in identifying sex chromosomes. Female heterogamety (ZW) has long been established in Bufo bufo, based on sex reversal and crossing experiments. Here, we investigate a sex-linked marker identified from a laboratory cross between Palearctic green toads (Bufo viridis subgroup). The F(1) offspring produced by a female Bufo balearicus and a male Bufo siculus were phenotypically sexed, displaying an even sex ratio. A sex-specific marker detected in highly reproducible AFLP genotypes was cloned. Sequencing revealed a noncoding, microsatellite-containing fragment. Reamplification and genotyping of families of this and a reciprocal cross showed B. siculus to be male heterogametic (XY) and suggested the same system for B. balearicus. Our results thus reveal a cryptic heterogametic transition within bufonid frogs and help explain patterns of hybrid fitness within the B. viridis subgroup. Turnovers of genetic sex-determination systems may be more frequent in amphibians than previously thought and thus contribute to the prevalence of homomorphic sex chromosomes in this group.

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The Pseudomonas aeruginosa toxin L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is a non-proteinogenic amino acid which is toxic for prokaryotes and eukaryotes. Production of AMB requires a five-gene cluster encoding a putative LysE-type transporter (AmbA), two non-ribosomal peptide synthetases (AmbB and AmbE), and two iron(II)/α-ketoglutarate-dependent oxygenases (AmbC and AmbD). Bioinformatics analysis predicts one thiolation (T) domain for AmbB and two T domains (T1 and T2) for AmbE, suggesting that AMB is generated by a processing step from a precursor tripeptide assembled on a thiotemplate. Using a combination of ATP-PPi exchange assays, aminoacylation assays, and mass spectrometry-based analysis of enzyme-bound substrates and pathway intermediates, the AmbB substrate was identified to be L-alanine (L-Ala), while the T1 and T2 domains of AmbE were loaded with L-glutamate (L-Glu) and L-Ala, respectively. Loading of L-Ala at T2 of AmbE occurred only in the presence of AmbB, indicative of a trans loading mechanism. In vitro assays performed with AmbB and AmbE revealed the dipeptide L-Glu-L-Ala at T1 and the tripeptide L-Ala-L-Glu-L-Ala attached at T2. When AmbC and AmbD were included in the assay, these peptides were no longer detected. Instead, an L-Ala-AMB-L-Ala tripeptide was found at T2. These data are in agreement with a biosynthetic model in which L-Glu is converted into AMB by the action of AmbC, AmbD, and tailoring domains of AmbE. The importance of the flanking L-Ala residues in the precursor tripeptide is discussed.

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The Fragile X mental retardation protein (FMRP) regulates neuronal RNA metabolism, and its absence or mutations leads to the Fragile X syndrome (FXS). The β-amyloid precursor protein (APP) is involved in Alzheimer's disease, plays a role in synapse formation, and is upregulated in intellectual disabilities. Here, we show that during mouse synaptogenesis and in human FXS fibroblasts, a dual dysregulation of APP and the α-secretase ADAM10 leads to the production of an excess of soluble APPα (sAPPα). In FXS, sAPPα signals through the metabotropic receptor that, activating the MAP kinase pathway, leads to synaptic and behavioral deficits. Modulation of ADAM10 activity in FXS reduces sAPPα levels, restoring translational control, synaptic morphology, and behavioral plasticity. Thus, proper control of ADAM10-mediated APP processing during a specific developmental postnatal stage is crucial for healthy spine formation and function(s). Downregulation of ADAM10 activity at synapses may be an effective strategy for ameliorating FXS phenotypes.

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Contrasting with birds and mammals, poikilothermic vertebrates often have homomorphic sex chromosomes, possibly resulting from high rates of sex-chromosome turnovers and/or occasional X-Y recombination. Strong support for the latter mechanism was provided by four species of European tree frogs, which inherited from a common ancestor (∼5 Ma) the same pair of homomorphic sex chromosomes (linkage group 1, LG1), harboring the candidate sex-determining gene Dmrt1. Here, we test sex linkage of LG1 across six additional species of the Eurasian Hyla radiation with divergence times ranging from 6 to 40 Ma. LG1 turns out to be sex linked in six of nine resolved cases. Mapping the patterns of sex linkage to the Hyla phylogeny reveals several transitions in sex-determination systems within the last 10 My, including one switch in heterogamety. Phylogenetic trees of DNA sequences along LG1 are consistent with occasional X-Y recombination in all species where LG1 is sex linked. These patterns argue against one of the main potential causes for turnovers, namely the accumulation of deleterious mutations on nonrecombining chromosomes. Sibship analyses show that LG1 recombination is strongly reduced in males from most species investigated, including some in which it is autosomal. Intrinsically low male recombination might facilitate the evolution of male heterogamety, and the presence of important genes from the sex-determination cascade might predispose LG1 to become a sex chromosome.

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This thesis studies intellectual property right (also: IPR) strategies from the perspective of high growth startup companies. Due to technology development and intellectualization of business, large part of companies’ assets are nowadays intangible. At the same time, the importance of protection instruments designed to protect these intangible assets, intellectual property rights, is increasing. Utilization of these instruments, however, requires understanding of the functioning of the IPR system, as well as financial resources. Startup companies aiming for growth need to be able compete with more established companies also in relation to intangible assets, but they might not have the required knowledge ot resources to fully utilize IPRs in their business. This research aims to understand what are the benefits a startup company can have from protecting their IPRs, and how can the company achieve those benefits. Based on a review of previous literature, altogether 11 benefits of IPR registration were recognized. To answer to the research questions, six half-structured interviews were conducted with experts form different fields, all with experience in working with startup companies and IPR issues. The interviews were analyzed using different methods of qualitative data analysis, mainly derived from grounded theory and case study methods. As a result, out of the 11 benefits recognized from earlier literature, 8 were recognized to be relevant for startup companies. The most central benefits were recognized to be linked with the financial lifecycle of the startup company, including increasing credibility of the startup and stimulating an investment. In addition it was noticed, that startup companies are mainly able to utilize these benefits at later stages of their lifecycle. However, to be able to utilize the benefits at later stages, the startup company needs to be aware of the functioning of the IPR system and might need to apply for appropriate protection already early on. As a result of this study, a three-step model was formed to describe different levels of IPR utilization. The first level of the model represents the minimum level of understanding that every startup company should have regarding IPRs. The second level views IPR strategy from a risk management perspective, including securing the minimum protection of the company’s own IPRs, contract management and establishing processes for handling IPR issues. The last stage reflects strategic use of IPRs. At this third stage intellectual property rights have a central role in the startup company’s business, and they are used in the company’s value creation.

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This investigation examined the effects of de institutionalization on the adaptive behaviour and adjustment of adults with intellectual disabilities (ID). In study 1, a meta-analysis was conducted with 23 studies on deinstitutionalization adaptive behaviour outcomes. Deinstitutionalization was associated with modest improvements in adaptive behaviour however outcomes varied across adaptive behaviour domains and other substantive variables. Clinical and service implications of these results were explicated. Noting the trends from the meta-analysis, study 2 used this information in refining and piloting an Agency Transition Survey used to evaluate community transitions for persons with ID. Information derived from the survey was found to be valuable and adequate for the effective evaluation of transitional success. Potential applications of the survey and meta-analysis results were illustrated.

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Individuals with intellectual disabilities (ID) as a group have been subject to abuse. Individuals with ID need to be made aware of their rights. The 3Rs: Rights, Respect and Responsibility Human Rights Project is promoting rights awareness in individuals with ID, their caregivers and family members. To be effeCtive, abuse prevention must include support from the whole organization and its processes. This research evaluated the impact of the 3Rs initiative on the organization. It focused particularly on descriptions of organizational change perceived by full-time staff and managers in response to the initiation of the 3Rs Project. Behavioural interviews were conducted and a thematic analysis was used to describe changes in the organizational culture and behavioural mechanisms maintaining these changes. Systemic barriers to change were also explored. The results indicate that the Association is effectively implementing and supporting the rights-based philosophy.