Thesis (Ph.D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 148 pages. Includes Vita. Includes bibliographical references.

No description available.

Prader-Willi syndrome (PWS) is a genetic disorder resulting from a mutation of chromosome 15. It can manifest in physiological characteristics, cognitive impairment, behavioural problems, and sometimes also psychiatric disturbances. Taking care of an individual with PWS has a detrimental impact on the primary caregiver and also affects others around them. This considered, the current study aimed to learn more about the experiences and challenges of individuals diagnosed with PWS and their primary caregivers, in Gauteng and North-West Provinces, South Africa. Purposive sampling was used to select five families which then participated in the study. Qualitative research was used to conduct the study. As it was also crucial to generate a comprehensive understanding of participant experiences, collective instrumental case studies were used ̶ making use of participatory action research, ethnography and elements of auto-ethnography. Data were gathered by conducting semi-structured interviews, which were then analysed using thematic analysis. The data were organized around certain topics and common themes which emerged in each case study and the findings were then integrated with the literature which had been extensively reviewed. Based on these experiences and challenges, interventions were suggested that addressed the challenges and needs of the PWS individuals, their caregivers and families, and those around them (including school teachers). The main findings confirmed that not all individuals diagnosed with PWS manifest all the physiological characteristics, psychiatric disturbances and behavioural problems which have been documented in the literature. Furthermore, the symptoms vary in severity from one individual to the next. Cognitive impairment was, however, common to all individuals in the study. The findings also suggest that having a child diagnosed with PWS has a significantly negative impact on the primary caregiver, and taking care of PWS children is emotionally overwhelming and time-consuming. The use of a client-centred approach, implementing behaviour therapy techniques and doing psycho-education, all proved to be effective in managing some of these behaviours displayed by the individual patients and the challenges experienced by primary caregivers. / Psychology / Ph. D. (Psychology)

Developmental specifics of individuals with Angelman and Prader - Willi syndrome as the basis for special educator's work The thesis deals in a complex way with the issue of two rare syndromes - Angelman and Prader- Willi syndrome. It describes the manifestations and genetic background, outlines the options for special education and rehabilitation interventions as well as selected medical and regime measures. The thesis informs about the category of rare diseases and also mentions the strategies for approach to these diseases used in the Czech Republic. It also comprises a list of organizations in the Czech Republic that deal with the Angelman and Prader - Willi syndrome and which associate parents and others interested in this topic. The end, the thesis comprises casuistry of two individuals, characteristic syndrome bearers, and conclusions of a questionnaire survey among parents. Surveys through questionnaires illustrate the specific characteristics of inidividuals that have been used to define areas of support. The goal of the thesis was to describe the possibilities for pedagogic and other interdisciplinary interventions, map the situation in the Czech Republic, and to provide more information about this issue to anyone interested.

Le syndrome de Prader-Willi est une maladie génétique rare. Les gènes candidats au SPW, dont le gène Necdin, sont régulés par l'empreinte génomique parentale : seul l'allèle paternel de ces gènes est exprimé, l'allèle maternel étant silencieux. Notre équipe a généré un modèle murin pour lequel l'allèle paternel de Necdin a été désactivé (+m/-p) et qui présente des similarités phénotypiques avec les patients PW. Ce phénotype est plus drastique chez les animaux -/-. Nous avons alors émis l'hypothèse que l'allèle maternel puisse avoir un rôle fonctionnel dans la survie des souris (+m/-p). L'expression de l'allèle maternel de Necdin est présente dans le système nerveux des souris (+m/-p). Cette expression, bien que faible au niveau transcriptionnel, est suffisante pour produire la protéine Necdin, ce qui a des conséquences cellulaires et physiologiques qui in fine permettent une amélioration du phénotype. Cette perte de silence de l'allèle maternel est également détectée dans l'hypothalamus de patients PW. Ces résultats révèlent une plasticité épigénétique inattendue qui permet d'envisager des perspectives thérapeutiques. / The Prader-Willi Syndrome (PWS) is a rare genetic disorder. Several genes, including NECDIN gene, are involved in the PWS. These genes are regulated by the genomic imprinting mechanism: only the paternal allele of these genes is expressed, their maternal allele being silenced. Our team has generated a mouse model in which the paternal allele of the Necdin gene has been deactivated (+m/-p). This model presents phenotypical similarities with PWS patients. We observed that mortality affects more -/- pups than +m/-p mice. Therefore we venture the hypothesis of a functional role of the maternal allele in mutant mice survival. We showed an expression of this allele in the nervous system of +m/-p mice. Though transcriptionnally low, that is sufficient to produce the Necdin protein and provoke cellular as well as physiological consequences that actively improve the phenotype. Importantly, a specific expression of the maternal NECDIN allele is also detected in hypothalamic brain sections of PWS patients. These results reveal an unexpected epigenetic flexibility that allow to contemplate a therapeutic pharmacological prospect.

A síndrome de Prader Willi (PWS) é uma doença de neurodesenvolvimento; a principal hipótese de causa de PWS é a ausência da expressão de SNORD116. O SNORD116 fica na região 15q11-q13 que apresenta vários genes com imprinting genômico e é conhecida por ser controlada pela região de controle de imprinting PWS (PWS-IC) que se localiza sobreposta à região promotora e ao exon 1 do gene SNRPN. Em camundongos, uma proteína zinc finger (Zfp57) foi descrita como importante para o estabelecimento e manutenção do imprinting no Snrpn. Através de análise do ENCODE do Genome Browser, verificamos que outra proteína zinc finger (ZNF274) se liga ao SNORD116. ZNF274 é conhecida por formar um complexo com TRIM28 e SETDB1 que inibe a expressão através da trimetilação da lisina 9 na histona 3 (H3K9me3). No atual estudo mostramos que ZNF274 se liga ao SNORD116 preferencialmente ao alelo materno nas células-tronco pluripotente induzidas (iPSCs). Adicionalmente, as proteínas TRIM28 e SETDB1, que formam um complexo com a ZNF274, estão presentes na região do SNORD116, e a modificação H3K9me3 ocorre preferencialmente no alelo materno nas iPSCs. Na análise funcional, mostramos que o knockdown de SETDB1 isoladamente ou combinado com o knockdown de ZNF274 causa aumento na expressão de SNRPN e SNORD116 nas iPSCs. Além disso, ocorre redução do H3K9me3 e aumento da modificação relacionada à ativação da transcrição, H3K4me2 (dimetilação da lisina 4 na histona 3), na PWS-IC. Os knockdowns também afetam a metilação de DNA, ocasionando o aumento de 5-hidroximetliação de citosinas na PWS-IC. Em outros tipos celulares estudados, neurônios derivados de iPSCs e SHEDs, ZNF274 e a modificação H3K9me3 ocorrem em ambos os alelos dentro do SNORD116. É possível que, nas iPSCs, este complexo proteja a região imprintada da desmetilação do DNA de proteína(s) que atue(m) nessa região somente em células pluripotentes. Nossos achados possibilitam melhor compreensão dos mecanismos envolvidos no imprinting da região 15q11-q13, principalmente do SNORD116, e, consequentemente, disponibiliza novas ferramentas para o desenvolvimento de futuras terapias para PWS. / Prader-Willi syndrome (PWS) is a neurodevelopmental disorder. Loss of paternal copies of the cluster of SNORD116 C/D box snoRNAs and their host transcript, 116HG, on human chromosome 15q11-q13 imprinted region is considered to be the major responsible for PWS. PWS-imprinting center (PWS-IC) regulates 15q11-q13 imprinting. PWS-IC is located upstream and in the exon 1 of SNURF-SNRPN gene. In mice, Zfp57 plays an important role in establishment and maintenance of Snrpn imprinting. In human, ENCODE database indicates that ZNF274 binds to SNORD116. Moreover, ZNF274 are C2H2/KRAB zinc finger proteins as Zfp57. We have investigated the mechanism of repression of the maternal SNORD116. Here, we report that the ZNF274, in association with the histone H3 lysine 9 (H3K9) methyltransferase SETDB1, is part of a complex that binds to the silent maternal but not to the active paternal alleles in induced pluripotent stem cells (iPSCs). Knockdown of SETDB1 in PWS-specific iPSCs causes a decrease in the accumulation of H3K9 trimethylation (H3K9me3) at SNORD116. We also show that upon knockdown of SETDB1 in PWS-specific iPSCs, expression of maternally silenced 116HG RNA is partially restored. SETDB1 knockdown in PWS iPSCs also disrupts DNA methylation at the PWS-IC where a decrease in 5-methylcytosine is observed in association with a concomitant increase in 5-hydroxymethylcytosine. In iPSCs-derived neurons and stem cells from human exfoliated teeth (SHEDs) ZNF274/SETDB1 complex binding and H3K9me3 modification occur in both alleles. These observations suggest that the ZNF274/SETDB1 complex bound to the SNORD116 cluster may protect the PWS-IC from DNA demethylation during early development, as indicated by iPSCs. Our findings reveal novel epigenetic mechanisms that function to repress the maternal 15q11-q13 region. The better understanding of epigenetic mechanisms provides new tools for future therapy research.

A síndrome de Prader Willi (PWS) é uma doença de neurodesenvolvimento; a principal hipótese de causa de PWS é a ausência da expressão de SNORD116. O SNORD116 fica na região 15q11-q13 que apresenta vários genes com imprinting genômico e é conhecida por ser controlada pela região de controle de imprinting PWS (PWS-IC) que se localiza sobreposta à região promotora e ao exon 1 do gene SNRPN. Em camundongos, uma proteína zinc finger (Zfp57) foi descrita como importante para o estabelecimento e manutenção do imprinting no Snrpn. Através de análise do ENCODE do Genome Browser, verificamos que outra proteína zinc finger (ZNF274) se liga ao SNORD116. ZNF274 é conhecida por formar um complexo com TRIM28 e SETDB1 que inibe a expressão através da trimetilação da lisina 9 na histona 3 (H3K9me3). No atual estudo mostramos que ZNF274 se liga ao SNORD116 preferencialmente ao alelo materno nas células-tronco pluripotente induzidas (iPSCs). Adicionalmente, as proteínas TRIM28 e SETDB1, que formam um complexo com a ZNF274, estão presentes na região do SNORD116, e a modificação H3K9me3 ocorre preferencialmente no alelo materno nas iPSCs. Na análise funcional, mostramos que o knockdown de SETDB1 isoladamente ou combinado com o knockdown de ZNF274 causa aumento na expressão de SNRPN e SNORD116 nas iPSCs. Além disso, ocorre redução do H3K9me3 e aumento da modificação relacionada à ativação da transcrição, H3K4me2 (dimetilação da lisina 4 na histona 3), na PWS-IC. Os knockdowns também afetam a metilação de DNA, ocasionando o aumento de 5-hidroximetliação de citosinas na PWS-IC. Em outros tipos celulares estudados, neurônios derivados de iPSCs e SHEDs, ZNF274 e a modificação H3K9me3 ocorrem em ambos os alelos dentro do SNORD116. É possível que, nas iPSCs, este complexo proteja a região imprintada da desmetilação do DNA de proteína(s) que atue(m) nessa região somente em células pluripotentes. Nossos achados possibilitam melhor compreensão dos mecanismos envolvidos no imprinting da região 15q11-q13, principalmente do SNORD116, e, consequentemente, disponibiliza novas ferramentas para o desenvolvimento de futuras terapias para PWS. / Prader-Willi syndrome (PWS) is a neurodevelopmental disorder. Loss of paternal copies of the cluster of SNORD116 C/D box snoRNAs and their host transcript, 116HG, on human chromosome 15q11-q13 imprinted region is considered to be the major responsible for PWS. PWS-imprinting center (PWS-IC) regulates 15q11-q13 imprinting. PWS-IC is located upstream and in the exon 1 of SNURF-SNRPN gene. In mice, Zfp57 plays an important role in establishment and maintenance of Snrpn imprinting. In human, ENCODE database indicates that ZNF274 binds to SNORD116. Moreover, ZNF274 are C2H2/KRAB zinc finger proteins as Zfp57. We have investigated the mechanism of repression of the maternal SNORD116. Here, we report that the ZNF274, in association with the histone H3 lysine 9 (H3K9) methyltransferase SETDB1, is part of a complex that binds to the silent maternal but not to the active paternal alleles in induced pluripotent stem cells (iPSCs). Knockdown of SETDB1 in PWS-specific iPSCs causes a decrease in the accumulation of H3K9 trimethylation (H3K9me3) at SNORD116. We also show that upon knockdown of SETDB1 in PWS-specific iPSCs, expression of maternally silenced 116HG RNA is partially restored. SETDB1 knockdown in PWS iPSCs also disrupts DNA methylation at the PWS-IC where a decrease in 5-methylcytosine is observed in association with a concomitant increase in 5-hydroxymethylcytosine. In iPSCs-derived neurons and stem cells from human exfoliated teeth (SHEDs) ZNF274/SETDB1 complex binding and H3K9me3 modification occur in both alleles. These observations suggest that the ZNF274/SETDB1 complex bound to the SNORD116 cluster may protect the PWS-IC from DNA demethylation during early development, as indicated by iPSCs. Our findings reveal novel epigenetic mechanisms that function to repress the maternal 15q11-q13 region. The better understanding of epigenetic mechanisms provides new tools for future therapy research.

Le syndrome de Prader-Willi (SPW) est une maladieneurodéveloppementale rare d’origine génétique dont les manifestationspsychologiques incluent une déficience intellectuelle légère à modérée, descomportements ritualisés, une obsession pour la nourriture, des accès de colèreet une labilité émotionnelle. Le premier objectif de ces études est d’appuyer lalittérature suggérant un déficit des fonctions exécutives dans le SPW. Ledeuxième objectif est d’évaluer s’il existe un déficit du traitement émotionneldans le SPW. Le troisième objectif est de déterminer si les effets modulateurs dela valeur émotionnelle sur l’efficience du contrôle exécutif sont exprimésdifférentiellement dans le SPW comparativement à la population saine. Deuxpré-expériences et cinq expériences ont été menées en utilisant des mesurescomportementales (pré-expériences 1, 2, expériences 1 à 5) et une associationentre mesures comportementales et mesures électrodermales (expériences 1, 2,3, 5). Les mesures comportementales montrent un ralentissement du traitementde l’information et une plus faible précision des réponses dans le SPW. Lesmesures physiologiques montrent des réponses de plus faible intensité et defaçon surprenante, plus précoces dans le SPW. Dans la majorité des cas, letraitement émotionnel de l’information est identique dans les deux groupes auniveau des mesures objectives. En revanche, l’évaluation subjective d’images àconnotation émotionnelle montre un biais de positivité dans le SPW. Enfin,l’efficience de la capacité de mise à jour de l’information est singulièrementaltérée dans le SPW lorsque l’environnement comporte des références à lanourriture. / Prader-Willi syndrome (PWS) is a rare neurodevelopmental geneticdisease whose psychological manifestations include mild to moderateintellectual disability, ritualistic behavior, obsession with food, temper tantrums,emotional lability and psychiatric disorders. The first aim of these studies is tosupport the growing evidence that PWS people show an impairment ofexecutive functions. The second aim is to investigate whether PWS people havean impairment of emotional processing. A third objective is to determine if themodulating effects of emotional significance on the efficiency of executivecontrol are differentially expressed in PWS in comparison to the healthypopulation. Two pre-experiments and five experiments were conducted usingbehavioral measures (pre-experiments 1, 2 and experiments 1 to 5) and bothbehavioral and electrodermal measures (experiments 1, 2, 3, 5). Behavioral datashowed a global slowness of processing and a lower response accuracy.Physiological data showed weaker but surprisingly earlier responses in the PWSgroup. In the majority of cases, emotional processing was identical in the twogroups at the level of objective measures. In contrast, the subjective rating ofpictures of emotional significance showed an overall positive rating bias in thePWS group. Finally, the updating capacity of working memory is singularlyhampered in PWS when the environment contains references to food.

A síndrome de Prader-Willi é uma desordem complexa neurogenética associada a três mecanismos genéticos distintos: deleção paterna da região 15q11-q13, dissomia uniparental materna do cromossomo 15 e defeitos no centro de imprinting genômico. As principais características da síndrome na primeira fase são a hipotonia de causa desconhecida em neonatos, dismorfismos, dificuldades de alimentação e hipogonadismo. O principal objetivo deste trabalho foi identificar portadores da síndrome de Prader-Willi em neonatos (pacientes com até 28 dias de vida) que apresentaram hipotonia neonatal em maternidades de São Paulo. Neste estudo foram analisados por teste de metilação dois pacientes com suspeita da síndrome de Prader-Willi que apresentavam os requisitos de inclusão do trabalho. Para que o teste fosse feito de maneira menos invasiva possível foi realizada a coleta de saliva dos pacientes por swab de bochecha, para extração de DNA. Em um período de um ano, foi confirmada a síndrome em um paciente do grupo. Mesmo com um número amostral reduzido já esperado pelo curto período de coleta, foi diagnosticado um caso precocemente, o que reforça a importância da inclusão da pesquisa para a síndrome de Prader-Willi no grupo de neonatos hipotônicos de causa desconhecida. / Prader-Willi syndrome is a complex neurogenetic disorder associated with three distinct genetic mechanisms. They are: the 15q11-q13 paternal deletion, maternal uniparental disomy of chromosome 15 and defects in the imprinting center. The main characteristics of the syndrome in the first phase are the hypotonia of unknown cause in neonates, dysmorphisms, feeding difficulties and hypogonadism. The main objective of this study was to identify neonates with Prader-Willi syndrome (patients up to 28 days old) that presented neonatal hypotonia. Two hospitals, Hospital das Clínicas da Faculdade de Medicina da Universidade São Paulo and Hospital Maternidade Amador Aguiar, collaborate with this investigation. In this study, two patients with hypotonia and poor suck satisfied the diagnostic criteria and were analyzed by methylation test. In order to make the test less invasive, saliva was collected from patients by swab. During a period of one year, the syndrome was confirmed in one patient in the group. Even with a reduced sample, already expected due to the short collection period, a case was early diagnosed, which reinforces the importance of including the genetic tests for Prader-Willi syndrome in the group of hypotonic neonates of unknown cause.

INTRODUÇÃO: A Síndrome de Prader-Willi (SPW) é uma doença multigênica causada pela perda de expressão de genes na região 15q11- q13. As principais características incluem hipotonia e disfunção hipotalâmica, que pode ser responsável pela hiperfagia levando a obesidade durante a infância, por controle ventilatório anormal e deficiência do Hormônio de Crescimento (GH). O objetivo deste estudo foi descrever e comparar o sono dos pacientes com SPW, descrever o IGF-I e correlacionar o IAH com IGF-I. MÉTODOS: Foram realizadas polissonografias em 17 pacientes (idade entre 3 anos e 18 anos) com SPW divididos em dois grupos, GH+ (n=9) e GH- (n=8). Trata-se de um estudo prospectivo realizado com pacientes do ambulatório de Endocrinologia do Instituto da Criança da Universidade de São Paulo, tendo sido obtido de seus prontuários resultados de IGF-I sérico anterior à realização do exame. RESULTADOS: Os grupos GH+ e GHforam homogêneos. Quatorze (82,3%) dos pacientes eram obesos, 8 (88,9%) GH+. Todos os pacientes apresentaram Índice de Apneia e Hipopneia (AH) 1. 88,2% dos pacientes apresentaram ronco. A eficiência do sono foi menor em 7 (41,2%) pacientes, sendo 6 (85,7%) do grupo GH+. 23,5% dos pacientes apresentaram porcentagem diminuída do sono de ondas lentas e 29,4% dos pacientes de sono REM. Cinco (29,5%) pacientes apresentaram latência de sono REM diminuída, sendo 2 (40%) paciente GH+ e 4 (23,6%) pacientes latência de sono aumentada, sendo 2 (50%) GH+. Todos os pacientes apresentaram fragmentação do sono. Os eventos mais comuns foram as hipopneias e as apneias obstrutivas. Três (17,7%) pacientes, sendo 1 (11,1%) GH+ apresentaram episódios de dessaturação importantes com mínima 65% e média 85%. Não foram encontradas correlação entre o IAH e IGF-I (p = 0,606). Não houve diferença estatisticamente significante entre os dados polissonográficos de ambos os grupos. CONCLUSÕES: Todos os pacientes apresentaram IAH 1, dessaturação de oxigênio com predomínio em sono REM e fragmentação do sono. Não foram encontradas diferenças na correlação do IGF-1 com IAH. Não foram encontradas diferenças entre os grupos GH+ e GH- em relação aos dados antropométricos e polissonográficos / BACKGROUND: Prader-Willi syndrome (PWS) is a multigenic disorder caused by the loss of expression of genes in the 15q11-q13 region. The main features include hypotonia and hypothalamic dysfunction that may be responsible for hyperphagia leading to obesity during childhood, abnormal ventilatory control and Growth Hormone (GH) deficiency. The aim of this study is to describe and compare the sleep of patients with PWS, describe the IGF-I and correlate IGF-I with AHI. METHODS: All polysomnographic (PSG) studies were performed in 17 patients (aged between 3 years and 18 years) with PWS divided in 2 groups, as follows: GH + (n = 9) and GH- (n = 8). This prospective study was conducted at the Endocrinologic Outpatient Clinic (Children\'s Hospital, University of São Paulo) and results of IGF-I serum were obtained from their medical records prior to the PSG. RESULTS: The groups GH + and GH-were homogeneous. 82,3% patients were obese, 8 (88.9%) GH +. All patients had AHI 1. 88,2% patients presented snoring. The sleep efficiency was lower in 7 (41.2%) patients, 6 (85.7%) GH +. 23,5% patients showed reduced percentage of slow wave sleep and 29,4% patients showed reduced percentage of REM sleep . Five (29.5%) patients had reduced REM latency, 2 (40%) GH + and 4 (23.6%) patients had increased REM latency, 2 (50%) GH+. All patients had sleep fragmentation. The most common events were hypopneas and obstructive apneas. Three (17.7%) patients, 1 (11.1%) GH+ had important desaturation (SatO2 minimum 65% and SatO2 average 85%. No correlation was found between the AHI and IGF-I (p = 0.606). There were no statistically significant differences between polysomnographic data from both groups. CONCLUSIONS: All patients had AHI 1, oxygen desaturation predominating in REM sleep and sleep fragmentation. No differences were found in the correlation of IGF-1 with IAH. No differences were found between groups GH + and GH- in relation to anthropometric and polysomnographic data