Made available in DSpace on 2016-08-17T18:39:45Z (GMT). No. of bitstreams: 1 4725.pdf: 4003213 bytes, checksum: c40eb861711bbe31a91e5b1600b14b63 (MD5) Previous issue date: 2012-09-21 / Universidade Federal de Sao Carlos / Intellectual disability (ID) is manifest sign of more than 2,000 different clinical conditions and is present in 5% of the population. Because it is a heterogeneous group of clinical conditions, with different causal factors and simultaneously involved, about 50% of patients with ID have no defined etiology. Chromosomal microdeletions, situations in which there is loss of a fragment of up to 5Mb of the genome resulting in haploinsufficiency of one or multiple genes, are one of the possible causes of ID. The aim of this study was to standardize genetic testing with the technique of MLPA (Multiplex Ligation Probe Amplification) to investigate the presence of microdeletion syndromes in a sample of patients with idiopathic DI or with diagnosis not yet confirmed by molecular genetic testing. The MLPA kit used (SALSA® MLPA® P064-B2 MR1) detected, at the same time, 11 microdeletion syndromes: 1p36 deletion, Sotos, Miller-Dieker, 22q11.2 deletion, Saethre-Chotzen, Prader-Willi, Angelman, Williams, Alagille, Smith-Magenis and Canavan. We selected 57 patients with idiopathic ID and facial dysmorphias, with normal conventional karyotyping and normal brain imaging studies. The presence of microdeletion was identified in 4 patients (7%), 3 patients had Williams syndrome and 1 had 22q11.2 deletion. The results reinforce the usefulness of MLPA in the etiologic research of ID, helping in the clinical management and familial genetic counseling. / Deficiência intelectual (DI) é sinal manifesto de mais de 2.000 condições clínicas diferentes e está presente em 5% da população. Por se tratar de um grupo heterogêneo de condições clínicas, com fatores causais distintos e simultaneamente envolvidos, cerca de 50% dos pacientes com DI não têm sua etiologia definida. Entre as possíveis causas de DI estão as microdeleções cromossômicas, situações nas quais há perda de um fragmento de até 5Mb do genoma, implicando na haploinsuficiência de um ou múltiplos genes. O objetivo desse trabalho foi padronizar testes genéticos fundamentados na técnica de MLPA (Amplificação de Múltiplas Sondas dependentes de Ligação) para investigar a presença de síndromes de microdeleção em uma amostra de pacientes com DI idiopática ou com hipótese diagnóstica ainda não confirmada por teste genético molecular. O kit de MLPA utilizado (SALSA® MLPA® P064-B2 MR1) detectava, simultaneamente, 11 síndromes de microdeleção: deleção 1p36, Sotos, Miller-Dieker, deleção 22q11.2, Saethre- Chotzen, Prader-Willi, Angelman, Williams, Alagille, Smith-Magenis e Canavan. Foram selecionados clinicamente 57 pacientes com DI e dismorfias faciais, com cariótipo convencional e exame de imagem de encéfalo normais. A presença de microdeleção foi identificada em 4 pacientes (7%), tendo sido detectados 3 pacientes com síndrome de Williams e 1 com deleção 22q11.2. Os resultados reforçam a utilidade da técnica de MLPA na investigação etiológica da DI, ajudando no manejo clínico dos pacientes e no aconselhamento genético familiar.

Des variants pathogéniques du gène TBC1D24 sont associés à des maladies génétiques dont la majorité sont transmises d’une façon autosomique récessive. Les phénotypes sont variables en termes de présentation clinique et de sévérité. Les formes les plus sévères causent une encéphalopathie épileptique (EIEE16) ou le syndrome DOORS qui est marqué par une surdité, des anomalies des ongles et des doigts, un déficit intellectuel et des convulsions qui sont souvent difficiles à contrôler. D’autres formes d’épilepsie incluent EPRPDC (Rolandic epilepsy with paroxysmal exercise-induce dystonia and writer's cramp), FIME (familial infantile myoclonic epilepsy), et PME (progressive myoclonus epilepsy). Une variant faux-sens spécifique est associée à une surdité autosomique dominante (DFNA65) qui se développe à l’âge adulte. Nous avons écrit un guide de pratique clinique qui inclut une revue de la littérature sur les phénotypes publiés chez les individus avec des variantes pathogénique du gène TBC1D24 avec de recommandations pour le suivi clinique de ces patients. De plus, une cohorte de huit patients avec déficience intellectuelle et épilepsie qui partagent une microdélétion sur le chromosome 16p13.3 contenant le gène TBC1D24 a été assemblée et caractérisée afin de définir un nouveau syndrome génétique. La région critique contient TBC1D24, ATP6V0C et PDPK1. Le phénotype similaire entre les huit individus suggère que l’haploinsuffisance pour TBC1D24, ATP6V0C et PDPK1 cause un nouveau syndrome génétique. L’etude des gènes essentiels pour le phénotype dans cette cohorte aide dans l’identification des nouveaux gènes candidates pour la déficience intellectuelle et épilepsie. / Pathogenic variants in the TBC1D24 gene are associated with genetic disorders, the majority of which are transmitted in an autosomal recessive manner. The phenotypes are variable in terms of clinical presentation and severity. The most severe forms cause epileptic encephalopathy (EIEE16) or DOORS syndrome which is marked by deafness, abnormalities of the nails and fingers, intellectual deficit and convulsions which are often difficult to control. Other forms of epilepsy include EPRPDC (Rolandic epilepsy with paroxysmal exercise-induce dystonia and writer's cramp), FIME (familial infantile myoclonic epilepsy), and PME (progressive myoclonus epilepsy). A specific missense variant is associated with autosomal dominant deafness (DFNA65) which develops in adulthood. A review of the literature of the published phenotypes observed in individuals with pathogenic variants in the TBC1D24 gene is presented here with recommendations for the clinical management of these patients. In addition, a group of eight patients with intellectual disability and epilepsy who share a microdeletion on chromosome 1613.3 containing the TBC1D24 gene were characterized in order to define a new genetic syndrome. The critical region contains TBC1D24, ATP6V0C and PDPK1. The significantly similar phenotype shared by the eight individuals suggests that haploinsufficiency for TBC1D24, ATP6V0C and PDPK1 causes a new genetic syndrome. Knowledge of the genes essential for the phenotype in this cohort helps in the identification of new candidate genes for intellectual disability and epilepsy.

Cytochrome c oxidase (COX) represents the terminal enzyme complex of respiratory chain metabolic pathway and it occurs as monomer, dimer or as a part of respiratory supercomplexes in the inner mitochondrial membrane. COX assembly process is complicated, highly regulated and depends on many ancillary proteins. Mutations in COX subunits, which are encoded by mitochondrial and nuclear DNA, or in genes encoding its assembly proteins are frequent cause of very severe mitochondrial disorders. SURF1 assembly protein participates in the first steps of COX assembly, but its exact function is not yet clarified. In humans, mutations of SURF1 gene lead to severe COX defect and fatal neurodegenerative disorder, Leigh syndrome. Knockout of SURF1 gene in mouse causes isolated COX defect as well, but less pronounced and without involvement of CNS. The aim of the thesis was detailed analysis of disturbed COX biogenesis in a condition of SURF1 gene mutations or SURF1 gene knockout, from assembly of COX monomer to interaction of COX into supercomplexes, and to the impact of isolated COX defect on other OXPHOS complexes. Mutations of SURF1 gene in patient's fibroblasts led to marked accumulation of COX assembly intermediates and to a defect in formation of functional COX monomer, which was preferentially built into an...

Cytochrome c oxidase (COX) represents the terminal enzyme complex of respiratory chain metabolic pathway and it occurs as monomer, dimer or as a part of respiratory supercomplexes in the inner mitochondrial membrane. COX assembly process is complicated, highly regulated and depends on many ancillary proteins. Mutations in COX subunits, which are encoded by mitochondrial and nuclear DNA, or in genes encoding its assembly proteins are frequent cause of very severe mitochondrial disorders. SURF1 assembly protein participates in the first steps of COX assembly, but its exact function is not yet clarified. In humans, mutations of SURF1 gene lead to severe COX defect and fatal neurodegenerative disorder, Leigh syndrome. Knockout of SURF1 gene in mouse causes isolated COX defect as well, but less pronounced and without involvement of CNS. The aim of the thesis was detailed analysis of disturbed COX biogenesis in a condition of SURF1 gene mutations or SURF1 gene knockout, from assembly of COX monomer to interaction of COX into supercomplexes, and to the impact of isolated COX defect on other OXPHOS complexes. Mutations of SURF1 gene in patient's fibroblasts led to marked accumulation of COX assembly intermediates and to a defect in formation of functional COX monomer, which was preferentially built into an...