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The present thesis belongs to the research area disability research and deal with specific aspects of cognition in individuals with Usher syndrome type 1 and 2. The subject has been investigated and is discussed within an interdisciplinary framework, though the theories applied and described are derived from the area of cognitive psychology. Usher syndrome is a rare genetic condition causing a combination of visual and hearing impairment: deafblindness. There is a congenital hearing loss that is profound in type 1 and moderate to severe in type 2. During mid-childhood symptoms of visual impairment, e.g. light sensitivity, emerge and a progressive loss of visual field follows as a result of the genetically caused eye disease Retinitis Pigmentosa. The syndrome has previously been well described with respect to the genetical and medical aspects, but there has been very little research with a cognitive perspective on the population. Studies 1 and 2 in the present thesis focused on children with Usher syndrome type 1 with cochlear implants and investigated phonological skills, lexical access, working memory and reading skill in the group. Studies 3 & 4 investigated the same cognitive abilities and theory of mind in adults with Usher syndrome type 2. In study 4 the performance on theory of mind in the adults with Usher syndrome type 2 was also compared to that of another group with genetically caused deafblindness: individuals with Alström syndrome. The results were that both the children and adults with Usher syndrome had significantly poorer phonological processing than the control groups with normal hearing. There was a large variation on performance on lexical access, especially in the group of children, however several individuals performed at the same level as the control group. Reading skill was found to be at level with the control groups’. There was also great variation in performance on ToM, however the majority of individuals performed similar to the control group with normal hearing and vision. The present project has resulted in some new knowledge on cognitive performance in  individuals with Usher syndrome type 1 and type 2. Performance in the participants with Usher syndrome can to a large extent can be understood by application of the models developed in previous research on populations with hearing impairment or deafness for understanding the impact of hearing with a hearing aid or cochlear implant. However, individuals with Usher syndrome experience additional difficulties in accessing information due to the progressive visual loss and the impact this has on performance is still largely unknown. Hence, the present project would recommend that interventions and support would be designed specifically to each individuals’ needs, with consideration of both the visual impairment and the hearing impairment. / Föreliggande avhandling tillhör ämnet handikappvetenskap och beskriver specifika kognitiva förmågor hos personer med Ushers syndrom typ 1 och 2. Avhandlingens ämne har undersökts utifrån ett tvärvetenskapligt perspektiv, även om de teorier som tillämpas och beskrivs huvudsakligen härrör inom området kognitiv psykologi. Ushers syndrom är en ovanlig genetisk åkomma som leder till kombinationen av syn- och hörselnedsättning: dövblindhet. Individer med typ 1 av syndromet har medfödd dövhet medan individer med typ 2 har en medfödd måttlig till grav hörselnedsättning. Någon gång i åldrarna 6-10 år börjar de första symptomen, till exempel nedsatt mörkerseende, på den genetiskt betingade progressiva synnedsättningen Retinitis Pigmentosa att framträda. Syndromet är väl beskrivet i forskningen med avseende på genetiska och medicinska aspekter, men det finns extremt lite tidigare forskning med kognitivt perspektiv om populationen. Studierna 1 och 2 i föreliggande avhandling fokuserade på barn med Ushers syndrom typ 1 och cochleaimplantat. Dessa studier undersökte fonologisk förmåga, lexikal access, arbetsminne och läsning i gruppen. Studie 3 undersökte samma kognitiva förmågor hos vuxna med typ 2 av syndromet. I studie 4 undersöktes även den sammansatta förmågan Theory of Mind hos de vuxna med typ 2 och deras prestation jämfördes både mot en kontroll grupp med normal hörsel och syn och en kontrollgrupp med annan typ av dövblindhet; Alström syndrom. Resultaten visade att både barnen och de vuxna med Ushers syndrom hade signifikant sämre fonologisk förmåga än kontrollgruppen med normal hörsel. Nivån på prestation varierade stort inom grupperna, särskilt mellan barnen med typ 1, och flera av individerna (barn och vuxna) presterade trots hörselnedsättningen på samma nivå som de normalhörande. Läsfärdigheten befanns vara i nivå med kontrollgrupperna. I den vuxna gruppen var det stor variation i prestation även på Theory of Mind, men de flesta av individerna presterade liknande som kontrollgruppen med normal hörsel och syn. Föreliggande projekt har resulterat i lite mer kunskap om kognitiva färdigheter hos individer med Ushers syndrom typ 1 och 2. De resultat som individerna med Ushers syndrome presterade kan till stor del förstås och tolkas genom tillämpning av teorier och modeller utvecklade för att den inverkan på kognitiva förmågor det har att ha nedsatt hörsel och höra med hjälp av hörselapparat eller cochleaimplantat. Dock tyder fynden i detta projekt även på att individer med Ushers syndrom på grund av den allvarliga synnedsättningen har ytterligare svårigheter att få tillgodogöra sig information, men i vilken utsträckning och på vilket sätt är ännu inte beskrivet. Utifrån fynden i föreliggande studie blev rekommendation att interventioner och stöd till personer med Ushers syndrom utformas specifikt till varje individ, med hänsyn taget både till hens grad av synnedsättning och hörselnedsättning.

Persons with deafblindness experience difficulties in daily life and they experience service to sometimes barrier. The overall aim of this thesis is therefore to discover, evaluate and explain: 1. mechanisms that might have impact on participation restrictions for people who have visual and hearing impairment i.e. deafblindness and 2. mechanisms that might barrier service to these people. Service is used as an umbrella term for health care, education and certain service for persons with disabilities. Materials from multiple sources have been used: literature (Study I No 96 papers). Interviews (Study I and V) with 32 and 3 adults with deafblindness respectively. Questionnaires (Study II and III): answered by 33 and 34 adults and youth with deafblindness. Patient records (Study IV and V): records from 9 and 3 adult females with USH I respectively. Materials mostly retrospectively cover the period from 2005 and about 40–50 years. Both quantitative and qualitative methods were used. International Classification of Functioning, Disability and Health (ICF) were consequently used as a framework to describe as well as a tool to analyze mechanisms. Further, the Ecological approach, Disability as a laminated system and Life course approach were used in order to evaluate and explain mechanisms. The conclusions that can be drawn from an ecological, laminated and life course approach are: Participation restrictions for people with deafblindness are far-reaching and are embedded in a complex process of interaction between the person with deafblindness and the environment. Services entail systematical barriers. In order to improve service it is extremely important to understand the role of participation restrictions in deafblindness. Primary activity limitation is to not see and hear enough for comprehension. Hence, not taking part in the visible and audible world is primary participation restriction. Performing activities without basic information includes risk. One important aspect of deafblindness is exposure. Persons with deafblindness require rehabilitation in a life perspective. In order to increase people’s participation and protection requirement of individually adapted support and assistive devices is necessary. ICF and the UN convention support service alterations.

Les cellules ciliées internes (CCIs) de la cochlée encodent les signaux acoustiques en impulsions électriques au niveau des synapses à ruban formées avec les fibres afférentes du nerf auditif. L'exocytose des vésicules glutamatergiques par les CCIs est déclenchée par l'activation des canaux calciques Cav1.3 et par l'otoferline, le senseur calcique intracellulaire présumé. Les mécanismes moléculaires précis régulant cette exocytose restent encore mal compris, notamment ceux à l’origine de sa précision temporelle, sa vitesse élevée en phase avec le signal acoustique("phase-locking" jusqu'à 1-2 kHz) et son infatigabilité. Nous montrons que la spécificité des synapses à ruban auditive et vestibulaire passe par une organisation spatiale spécifique des canaux Cav1.3 dans les zones actives. Les CCIs utilisent différentes isoformes de canaux Cav1.3, notamment des isoformes courtes tronquées dans leur partie C-terminale. Ces isoformes courtes (Cav1.343S et Cav1.342A) sont essentiellement impliquées dans le déclenchement et dans l'adaptation rapide de l'exocytose. Cette adaptation se réalise au niveau des canaux Cav1.3 à la fois en intracellulaire par le Ca2+ et en extracellulaire parles protons secrétés lors de l'exocytose. Les isoformes longues (Cav1.342L et Cav1.3∆44),positionnées en périphérie du ruban, réguleraient le recrutement vésiculaire. Par ailleurs, nous montrons que l'organisation spatiale des canaux Cav1.3 est dépendante d'un cytosquelette d'actine-F au ruban synaptique. La clarine 1 (protéine Usher IIIA) interagirait avec l'actine-F, l'harmonine (protéine PDZ, Usher IC) et la sous-unité β2 des canaux calciques pour organiser les canaux Cav1.3 dans les zones actives. / Cochlear inner hair cells (IHCs) encode acoustic signals into nerve impulses at their ribbon synapses formed with the auditory afferent fibers. The exocytosis of glutamatergic vesicles is triggered by voltage activation of Cav1.3 channels and requires otoferlin, the putative intracellular Ca2+ sensor. The precise molecular mechanisms of exocytosis still remain elusive, notably the mechanisms allowing the temporal precision, the high rates of vesicular fusion (high frequency phase-locking with sound) and the indefatigability of the process. We show here that exocytosis in auditory and vestibular hair cells relies on a specific tight spatial organization of Cav1.3 channels at the active zones. Auditory IHCs use different Cav1.3isoforms, notably short C-terminal isoforms (Cav1.343S et Cav1.342A). These short Cav1.3isoforms essentially trigger the RRP exocytosis (Readily Releasable Pool of vesicles) and are at the origin of its fast adaptation. This fast exocytotic adaptation is based both on an intracellularCa2+ dependant inactivation of the Ca2+ current and on its extracellular block by exocytosed protons. Long Cav1.3 isoforms (Cav1.342L et Cav1.3∆44) regulate the vesicular recruitment at the active zones. Furthermore, our results show that a synaptic actin cytoskeleton is essential for the tight spatial organization of the Cav1.3 channels at the ribbons. Clarin 1 (Usher IIIA protein),through its interactions with the F-actin network, harmonin (PDZ protein, Usher IC) and the Ca2+channel β2 subunit, is required to maintain the tight organization of Cav1.3 channels at the ribbon synapses.

Le syndrome d’Usher (USH) associe une surdité neurosensorielle congénitale et une perte progressive de la vision par rétinite pigmentaire. Pendant ma thèse, l’essentiel de mon travail a porté sur un gène responsable du syndrome d’Usher de type 2, USH2A. Ce gène code pour l’usherine, une protéine associée aux liens fibreux interstéréociliaires situés à la base de la touffe ciliaire des cellules ciliées de la cochlée. Ces liens transitoires disparaissent autour du 9e jour post-natal (P9), chez la souris et le complexe moléculaire associé à ces liens inclut l’usherine, adgrv1 (un récepteur membranaire couplé aux protéines G), la whirline, et pdzd7 (deux protéines sous-membranaires d’échafaudage contenant des domaines PDZ). Des travaux précédents ont montré que l’interaction de ces quatre protéines était nécessaire à un développement correct de la touffe ciliaire, qui lui-même conditionne la transduction mécano-électrique opérée par les cellules ciliées. Pendant ma thèse, j’ai étudié les effets, à court terme et à long terme, de l’absence de la plus longue des 2 isoformes connues de l’usherine, l’isoforme-b transmembranaire, sur des souris mutantes pour le gène Ush2a (Ush2aΔTM/ΔTM). Chez ces souris, j’ai effectué des mesures de courants de transduction mécano-électrique, des enregistrements des potentiels évoqués auditifs (PEA), des tests de masquage auditif, et une analyse morphologique des cellules ciliées par imagerie au microscope électronique à balayage. Ainsi, j’ai pu montrer que les liens interstéréociliaires basaux étaient présents à P4 et que les courants de transduction mécano-électrique étaient normaux à P7. L’absence de l’isoforme-b de l’usherine n’a, en fait, que très peu de conséquences morphologiques et fonctionnelles sur la touffe ciliaire des cellules ciliées de la cochlée durant les 3 ou 4 premiers mois de vie chez la souris. A partir de l’âge de 4 mois cependant, les souris Ush2aΔTM/ΔTM souffrent d’une perte progressive de l’audition et d’anomalies de la sélectivité dans l’analyse des fréquences du son, dues surtout à un dysfonctionnement des cellules ciliées externes. Ces résultats viennent alimenter le débat sur le caractère progressif de la surdité du syndrome d’Usher de type 2A. La surdité des patients USH2A est considérée comme étant le plus souvent non progressive, mais plusieurs études ont révélé que certains patients souffrent en fait d’une surdité progressive. Mon travail a permis de montrer que chez la souris, la surdité en rapport avec des mutations d’Ush2a peut également être progressive. L’existence potentielle d’une fenêtre temporelle chez les patients USH2A dont la surdité moins sévère à la naissance, va ensuite s’aggraver, pourrait permettre d’envisager dans le futur un traitement curatif précoce du déficit auditif de ces patients, par thérapie génique. / Usher syndrome (USH) is characterised by a sensorineural congenital deafness and a progressive loss of vision by retinitis pigmentosa. During my PhD, my main focus of study was a gene responsible for Usher syndrome type 2, USH2A. This gene codes for usherin, a protein associated with the fibrous links located at the base of the hair bundle of cochlear, and vestibular hair cells. In mice, these transitory links start to disappear as of postnatal day 9 (P9), and the molecular complex with which they are associated is composed of usherin, adgrv1 (an adhesion G protein coupled receptor), whirlin, and pdzd7 (two submembranous PDZ domain-containing scaffold proteins). Previous work has shown that the interaction in between these 4 proteins is essential for the development of the hair bundle, the structure responsible for the initiation of the mechano-electrical transduction (MET) process in the hair cells. During my thesis, I studied the short term and long term effects of the absence of the longest of the 2 usherin isoforms, the transmembrane b-isoform, in mice carrying a mutation in the Ush2a gene (Ush2aΔTM/ΔTM). In these mice, I measured mechano-electrical currents, auditory brainstem responses, undertook auditory masking tests, and analysed scanning electron micrographs of cochlear hair bundles. Through this work, I showed that basal lateral links similar to ankle links could be observed on P4, and that MET currents were normal on P7. The absence of the long b-isoform of usherin actually has very little effect on the morphology or the function of the cochlear hair bundle in mice, until 3 or 4 months of age. As of 4 months old however, Ush2aΔTM/ΔTM mice suffer from a progressive hearing loss, and frequency selectivity defects, mainly cause by a dysfunction of outer hair cells. These results will further add to the debate on whether the hearing loss in Usher syndrome type 2A is progressive or not. Hearing loss in USH2A patients is generally considered non progressive, but several studies have given indication to the contrary. My work has shown that in mice, deafness caused by mutations to the Ush2a gene can also follow a progressive pattern. The potential existence of this temporal window in USH2A patients whose hearing impairment is less severe at birth, but gets worse over time, could allow clinicians to use gene therapy as curative treatment for patients who fall into this category.

New strategies are needed to counter the growing problem of bacterial resistance to antibiotics. One such strategy is to design compounds that target bacterial virulence, which could work separately or in concert with conventional bacteriostatic or bactericidal antibiotics. Pilicides are a class of compounds based on a ring-fused 2-pyridone scaffold that target bacterial virulence by blocking the chaperone/usher pathway in E. coli and thereby inhibit the assembly of pili. This thesis describes the design, synthesis, and biological evaluation of compounds based on the pilicide scaffold with the goal of improving the pilicides and expanding their utility. Synthetic pathways have been developed to enable the introduction of substituents at the C-2 position of the pilicide scaffold. Biological evaluation of these compounds demonstrated that some C-2 substituents give rise to significant increases in potency. X-ray crystallography was used to elucidate the structural basis of this improved biological activity. Furthermore, improved methods for the preparation of oxygen-analogues and C-7 substituted derivatives of the pilicide scaffold have been developed. These new methods were used in combination with existing strategies to decorate the pilicide scaffold as part of a multivariate design approach to improve the pilicides and generate structure activity relationships (SARs). Fluorescent pilicides were prepared using a strategy where selected substituents were replaced with fluorophores having similar physicochemical properties as the original substituents. Many of the synthesized fluorescent compounds displayed potent pilicide activities and can thus be used to study the complex interactions between pilicide and bacteria. For example, when E. coli was treated with fluorescent pilicides, it was found that the compounds were not uniformly distributed throughout the bacterial population, suggesting that the compounds are primarily associated to bacteria with specific properties. Finally, by studying compounds designed to inhibit the aggregation of Aβ, it was found that some compounds based on the pilicide scaffold inhibit the formation of the functional bacterial amyloid fibers known as curli; these compounds are referred to as 'curlicides'. Some of the curlicides also prevent the formation of pili and thus exhibit dual pilicide-curlicide activity. The potential utility of such 'dual-action' compounds was highlighted by a study of one of the more potent dual pilicide-curlicides in a murine UTI model were the compound was found to significantly attenuate virulence in vivo.

The present thesis concerns people with Usher syndrome (USH) and their health. People with USH have a congenital hearing loss of various degrees and an eye disease with a progressive course; for some, the balance is also affected. Three clinical groups have been identified 1, 2 and 3, and 13 genes have currently been identified. USH is the most common cause of deafblindness. Clinical knowledge and the limited research that exists have shown that people with deafblindness can experience difficulties in everyday life. Depression, anxiety and social withdrawal have been described. The general aim of the present thesis was to describe the health of people with USH. The empirical material employed was based on an extensive survey in which people with USH answered two questionnaires concerning health, anxiety, depression, social trust, work, health-care, financial situation, and alcohol and drug use. The focus of the present thesis is on general health, physical health and psychological health, social trust and finance. Three studies in the present theses focus on USH1, 2 and 3, respectively; finally, the fourth study provides an in-group comparison of people with USH. The results of studies I and III are compared with a crosssection of the Swedish population. The results revealed poor physical and psychological health, a lack of social trust and a strained financial situation regardless of clinical diagnosis. The discussion stresses the importance of taking a biopsychosocial approach when describing the health of people with USH, in which previous research is lacking. Additional research should focus on the mechanisms at different levels that affect people with USH and their health from a life- course perspective. Furthermore, research should include a salutogenic perspective to explore the resources and strengths of people with USH.

Deafblindness is a combined impairment of vision and hearing with an incidence of about 1: 8000 children and 1: 5500 adults. The most common genetic causes are the Stickler (STL) and Usher (USH) syndromes. The main goal of this work is to provide an up-to-date overview of STL and USH in the Czech and Slovak Republic (CR and SR), to determine the correlations between the genotype and phenotype in our population and the associated diagnostic criteria. Using sequencing and MLPA we examined 45 patients from 28 families for suspected STL. We found potentially causal variants of STL genes in 39 patients from 22 families. Fifteen different COL2A1 variants (8 being novel) were found in 28 patients from 18 families and 4 novel COL11A1 variants were found in 11 patients from 4 families. We identified the cause of the disease in 79 % of the families. The USH study involved 30 patients from 27 families. The most frequent cause was USH2A pathogenic variants, i.e. 19 variants in 14 families, 9 being novel. Less common were pathogenic variants in MYO7A (6 variants in 3 families, 5 being novel), USH1C and CDH23 (3 variants, 2 being novel, in 2 families both) genes. In 2 families, compound heterozygosity was found for variants in two different USH genes. The deafblindness etiology was clarified for 24 patients from...

The work focuses on molecular genetic testing of patients with Usher syndrome to confirm the diagnosis, to determine the causal cause of the disease and describe new mutations causing Usher syndrome in Czech patients. Usher syndrome is a clinically and genetically heterogeneous disease that is the most common cause of hereditary deafblindness. Based on responsible genes and disease onset is classified into three clinical subtypes. Given the fact that there is currently no specific treatment, there is a need to understand the pathophysiology of this disease and to broaden the spectrum of causal mutations. The theoretical part of the thesis deals with the anatomy of the eye, especially the structure of the retina. Attention is also paid to retinal diseases, such as the progressive loss of vision characteristic for retinitis pigmentosa (RP). RP may occur either as an isolated disorder or also affecting other organs, so-called syndromic RP. Classic syndromic RP includes Usher's syndrome, which the work mainly deals with. The theoretical part of the thesis describes mainly the mechanism of the disease, the functions of individual Usher proteins and the genes that encode these proteins. The haplotype analysis has been previously done for the most common mutations causing Usher's syndrome in Europe Based...