Made available in DSpace on 2014-06-11T19:26:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-24Bitstream added on 2014-06-13T19:33:15Z : No. of bitstreams: 1 martins_alb_me_sjrp.pdf: 586478 bytes, checksum: aa86803b63525f77a66d762d487c4983 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As Doenças do Espectro Autístico incluem o Autismo, o Transtorno Invasivo do Desenvolvimento Sem Outra Especificação e a Síndrome de Asperger. A etiologia é muito discutida, devido a sua variação e complexidade. São doenças que se manifestam nos três primeiros anos de vida, com uma variação clínica que inclui comportamento ritualístico, fala ausente ou pouco desenvolvida, além de problemas graves de relacionamento. Em 5 a 37 % dos casos são observadas em comorbidade com outras afecções. Em indivíduos com estas doenças já foram descritas alterações em todos os cromossomos e há genes propostos como candidatos de estarem envolvidos na etiopatogenia. Também, há relatos de casos com alterações subteloméricas, especialmente deleções, envolvendo as extremidades distais dos braços longos dos cromossomos 2 e 22. Mais recentemente foram observadas mutações no gene SHANK3, que está localizado em 22q13.3, na população com Doenças do Espectro Autístico. Este trabalho apresenta os resultados de um estudo citogenético e molecular realizado em 48 indivíduos com doenças do espectro autístico. Foram estudados o cariótipo por bandamento GTG convencional, as regiões 2q37 e 22q13 pela técnica de bandamento GTG em alta resolução, os éxons 8 e 22 do gene SHANK3 por seqüenciamento direto. A análise cariotípica convencional e dos éxons 8 e 22 revelaram resultados normais. A análise em alta resolução de um indivíduo mostrou resultado com possível deleção em 2q37, que não foi confirmada por técnica complementar. O número restrito de pacientes estudados deve ser considerado, porém pode ser sugerido que alterações em 2q37, 22q13 e dos éxons 8 e 22 do gene SHANK3, sejam eventos mais raros do que se supunha em Doenças do Espectro Autístico e sua investigação pode ser indicada na triagem de pacientes e para o aconselhamento genético... / The autism spectrum disorders including autism, Pervasive Developmental Disorder Not Otherwise Specified and Asperger syndrome. The etiology is much debated due to its variation and complexity. These are disorders that are manifested in the first three years of life, with a clinical variant that includes ritualistic behavior, speech absent or poorly developed, in addition to serious relationship. In 5 to 37% of cases are observed in association with other diseases. In individuals with these diseases have been described changes in all chromosomes and genes are proposed as candidates to be involved in pathogenesis. Also, there are reports of cases with subtelomeric changes, especially deletions involving the distal ends of the long arms of chromosomes 2 and 22. More recently, mutations were observed in the gene SHANK3, which is located on 22q13.3, in the population with autism spectrum disorders. This paper presents the results of a cytogenetic and molecular study performed in 48 individuals with autistic spectrum disorders. We studied the karyotype by GTG conventional regions 2q37 and 22q13 by GTG banding technique in high resolution, the exons 8 and 22 SHANK3 gene by direct sequencing. The conventional karyotype analysis and exons 8 and 22 point normal results. The high resolution analysis of an individual with demonstrated results possible deletion in 2q37, which was not confirmed by complementary technique. The small number of patients should be considered, but may be suggested that changes in 2q37, 22q13 and exons 8 and 22 of the gene SHANK3, are more rare than previously thought on the autism spectrum disorders and their investigation may be indicated in screening of patients for genetic counseling of families is not justified. However, these investigations could be cited in this population when it is selected for the presence of dysmorphic features indicative of possible... (Complete abstract click electronic access below)

Smith-Magenis syndrome (SMS) is a multiple congenital abnormalities intellectual disability syndrome that results from a deletion of chromosome 17p11.2 or mutation of the retinoic acid inducted one gene (RAI1). SMS is characterized by a multitude of phenotypic features including craniofacial defects, short stature, obesity, intellectual disability, self-abusive behavior, sleep disturbance and behavioral abnormalities. Interestingly, although SMS is a clearly defined syndrome with a known molecular change at its foundation, ~40% of all candidate cases sent to the Elsea lab for evaluation do not have a mutation or deletion of RAI1. We hypothesize that at least one other locus must be responsible for this Smith-Magenis-like (SMS-like) phenotype. To address this hypothesis, we first compiled a cohort of 52 subjects who had been referred to the Elsea lab for a clinical diagnosis of SMS. Once these individuals were confirmed to not have an RAI1 mutation or deletion, their phenotypes were compiled and statically analyzed to distinguish whether SMS and SMS-like cohorts are different in the prevalence of the core phenotypes of SMS such as, but not limited to, sleep disturbance, self-abusive behavior and developmental delay. SMS-like and SMS cohorts are not different in prevalence for these core features. Next, all SMS-like subjects were sent for whole genome array comparative genomic hybridization (aCGH) to identify duplications or deletions of each individual’s genome which contribute to the phenotype observed. We identified 6 pathogenic copy number variants (CNVs) in six individuals which contribute directly to the clinical phenotype, including two del(2)(q37). This study enabled us to draw relationships between SMS and other syndromes that had never been appreciated before and helped to identify pathways in which RAI1 may function. Using the data from our SMS-like study we were able to further characterize two known syndromes; Deletion 2q37 syndrome (brachydactyly mental retardation syndrome) and deletion 2q23 syndrome. With regard to deletion 2q37, syndrome we used genomic data from known and new deletion 2q37 subjects to refine the critical region to one gene: the histone deacetylase 4 gene (HDAC4). Using both clinical and molecular clues, we were able to identify one subject from our SMS-like cohort who has an insertion in HDAC4 which results in a premature stop codon. We conclude from this study that mutation of HDAC4 results in brachydactyly mental retardation syndrome. With regard to deletion 2q23 syndrome there were only five known cases in the published literature to which we were able to add two more. Using as similar approach to our del2q37 study we refined the critical region for this syndrome to one gene, the methyl binding domain 5 gene (MBD5). Using a molecular and clinical approach we were able to conclude that haploinsufficiency of MBD5 results in the core phenotypes seen in del2q23 syndrome including microcephaly, intellectual disabilities, severe speech impairment, and seizures. Using all the data generated from the three previous studies we set out to characterize the molecular function of RAI1. We hypothesize that RAI1 is a transcription factor that regulates gene expression of core genes involved in development, neurological function, and circadian rhythm. Using a ChIP-chip based approach we identified 257 transcripts we believe RAI1 regulates. Following up on these transcripts, using in vitro and in vivo methods, we have been able to conclude that RAI1 is a positive regulator of CLOCK, the master regulator of the central circadian cycle. Taken together, these studies have given us insight into the specific molecular changes that contribute to SMS and SMS-like syndromes. We have unveiled pathways and genes which are important to normal human development and behavior and identified novel functions of RAI1. These studies will provide the foundation for the future discovery of the pathways affected.