Diagnóstico molecular da doença de Huntington em pacientes brasileiros

Huntington disease (HD) is a progressive neurodegenerative disorder with autosomal dominant inheritance, characterized by choreiform movements and cognitive impairment. Onset of symptoms is around 40 years of age and progression to death occurs in approximately 10 to 15 years from the time of disease onset. HD is associated with an unstable CAG repeat expansion at the 5' and of the IT15 gene. We have genotyped the CAG repeat in the IT15 gene in 44 Brazilian individuals (42 patients and 2 unaffected family members) belonging to 34 unrelated families thought to segregate HD. We found one expanded CAG allele in 32 individuals (76%) belonging to 25 unrelated families. In these HD patients, expanded alleles varied from 43 to 73 CAG units and normal alleles varied from 18 to 26 CAGs. A significant negative correlation between age at onset of symptoms and size of the expanded CAG allele was found (r=0.6; p=0.0001); however, the size of the expanded CAG repeat could explain only about 40% of the variability in age at onset (r2=0.4). In addition, we genotyped 25 unrelated control individuals (total of 50 alleles) and found normal CAG repeats varying from 16 to 33 units. The percentage of heterozigocity of the normal allele in the control population was 88%. In conclusion, our results showed that not all patients with the HD phenotype carried the expansion at the IT15 gene. Furthermore, molecular diagnosis was possible in all individuals, since no alleles of intermediate size were found. Therefore, molecular confirmation of the clinical diagnosis in HD should be sought in all suspected patients, making it possible for adequate genetic counseling.A doença de Huntington (HD) é afecção neurodegenerativa com padrão de herança autossômica dominante caracterizada por movimentos involuntários coreiformes e alterações cognitivas. O início dos sintomas ocorre em torno dos 40 de idade, progredindo até a morte em um período de aproximadamente 10 a 15 anos após o início da doença. A HD está associada a uma expansão trinucleotídica CAG presente na porção 5' do gene IT15. Nós investigamos a repetição CAG no gene IT15 em 44 indivíduos brasileiros (42 pacientes e 2 membros não afetados de uma família) pertencentes a 34 famílias não relacionadas com diagnóstico provável de HD. Um alelo CAG expandido foi encontrado em 32 indivíduos (76%) pertencentes a 25 famílias não relacionadas. Nos pacientes com a mutação HD, os alelos expandidos variaram de 43 a 73 unidades de repetição CAG e os alelos normais apresentaram variação de 18 a 26 CAGs. Correlação negativa significativa foi encontrada entre a idade de início dos sintomas e o tamanho da expansão trinucleotídica CAG (r=0,6; p=0,0001); no entanto, o tamanho da repetição CAG expandida foi capaz de explicar somente 40% da variação encontrada na idade de início da doença (r2=0,4). Além disso, nós genotipamos um total de 25 indivíduos pertencentes a um grupo controle da população brasileira (total de 50 alelos), sendo que o alelo normal apresentou variação de 16 a 33 unidades de repetição CAG. A porcentagem de heterozigozidade do alelo normal na população brasileira controle foi 88%. Em conclusão, nossos resultados mostraram que nem todos os pacientes com fenótipo ``HD'' possuíam a expansão CAG no gene IT15. O diagnóstico molecular foi possível em todos os indivíduos analisados nesse estudo, não sendo encontrada em nossa amostra nenhum alelo de tamanho intermediário. Portanto, nós recomendamos que a confirmação molecular do diagnóstico na HD deva ser realizada em todos os casos suspeitos, a fim de proporcionar subsídios para um aconselhamento genético adequado.111

Rqc: A Bioconductor Package for Quality Control of High-Throughput Sequencing Data

As sequencing costs drop with the constant improvements in the field, next-generation sequencing becomes one of the most used technologies in biological research. Sequencing technology allows the detailed characterization of events at the molecular level, including gene expression, genomic sequence and structural variants. Such experiments result in billions of sequenced nucleotides and each one of them is associated to a quality score. Several software tools allow the quality assessment of whole experiments. However, users need to switch between software environments to perform all steps of data analysis, adding an extra layer of complexity to the data analysis workflow. We developed Rqc, a Bioconductor package designed to assist the analyst during assessment of high-throughput sequencing data quality. The package uses parallel computing strategies to optimize large data sets processing, regardless of the sequencing platform. We created new data quality visualization strategies by using established analytical procedures. That improves the ability of identifying patterns that may affect downstream procedures, including undesired sources technical variability. The software provides a framework for writing customized reports that integrates seamlessly to the R/Bioconductor environment, including publication-ready images. The package also offers an interactive tool to generate quality reports dynamically. Rqc is implemented in R and it is freely available through the Bioconductor project (https://bioconductor.org/packages/Rqc/) for Windows, Linux and Mac OS X operating systems

Clinical Features And Management Of Hereditary Spastic Paraplegia.

Hereditary spastic paraplegia (HSP) is a group of genetically-determined disorders characterized by progressive spasticity and weakness of lower limbs. An apparently sporadic case of adult-onset spastic paraplegia is a frequent clinical problem and a significant proportion of cases are likely to be of genetic origin. HSP is clinically divided into pure and complicated forms. The later present with a wide range of additional neurological and systemic features. To date, there are up to 60 genetic subtypes described. All modes of monogenic inheritance have been described: autosomal dominant, autosomal recessive, X-linked and mitochondrial traits. Recent advances point to abnormal axonal transport as a key mechanism leading to the degeneration of the long motor neuron axons in the central nervous system in HSP. In this review we aim to address recent advances in the field, placing emphasis on key diagnostic features that will help practicing neurologists to identify and manage these conditions.72219-2

Recent developments in the genetics of childhood epileptic encephalopathies: impact in clinical practice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Recent advances in molecular genetics led to the discovery of several genes for childhood epileptic encephalopathies (CEEs). As the knowledge about the genes associated with this group of disorders develops, it becomes evident that CEEs present a number of specific genetic characteristics, which will influence the use of molecular testing for clinical purposes. Among these, there are the presence of marked genetic heterogeneity and the high frequency of de novo mutations. Therefore, the main objectives of this review paper are to present and discuss current knowledge regarding i) new genetic findings in CEEs, ii) phenotype-genotype correlations in different forms of CEEs; and, most importantly, iii) the impact of these new findings in clinical practice. Accompanying this text we have included a comprehensive table, containing the list of genes currently known to be involved in the etiology of CEEs.Recent advances in molecular genetics led to the discovery of several genes for childhood epileptic encephalopathies (CEEs). As the knowledge about the genes associated with this group of disorders develops, it becomes evident that CEEs present a number o7311946958FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)sem informaçãosem informaçã

Aspectos clínicos e manejo das paraplegias espásticas hereditárias

Hereditary spastic paraplegia (HSP) is a group of genetically-determined disorders characterized by progressive spasticity and weakness of lower limbs. An apparently sporadic case of adult-onset spastic paraplegia is a frequent clinical problem and a significant proportion of cases are likely to be of genetic origin. HSP is clinically divided into pure and complicated forms. The later present with a wide range of additional neurological and systemic features. To date, there are up to 60 genetic subtypes described. All modes of monogenic inheritance have been described: autosomal dominant, autosomal recessive, X-linked and mitochondrial traits. Recent advances point to abnormal axonal transport as a key mechanism leading to the degeneration of the long motor neuron axons in the central nervous system in HSP. In this review we aim to address recent advances in the field, placing emphasis on key diagnostic features that will help practicing neurologists to identify and manage these conditions.Paraplegias espásticas hereditárias (PEH) constituem um grupo de desordens geneticamente determinadas caracterizadas por espasticidade e paraparesia de progressão insidiosa. Paraplegia espástica aparentemente esporádica de início no adulto constitui problema frequente na prática neurológica. Evidências recentes sugerem que uma proporção significativa destes casos é geneticamente determinada. O grupo das PEH é dividido clinicamente em formas puras e complicadas de acordo com a concomitância de outras manifestações clinicas e neurológicas. Até o momento 60 tipos genéticos foram identificados. Todos os modos de herança monogênica já foram descritos: autossômica dominante, autossômica recessiva, ligada ao X e mitocondrial. Avanços recentes indicam que alterações do transporte axonal estão implicadas na degeneração dos longos axônios motores no sistema nervoso central na PEH. Nesta revisão abordamos recentes avanços na área com ênfase nos aspectos clínicos chave que ajudam o neurologista geral no diagnóstico e manejo correto deste grupo de doenças.21922

Evolução da epilepsia de lobo temporal mesial familiar

OBJECTIVE: To analyze seizure outcome in individuals with familial mesial temporal lobe epilepsy (FMTLE). METHOD: We followed prospectively 64 individuals with FMTLE and 37 asymptomatic individuals belonging to 28 families. RESULTS: Patients with FMTLE had a mean follow up was 93.4 ± 15.8 months. At baseline they were divided in benign (n = 29), remission (n = 28) and refractory (n = 7). At last follow up visit 41.4% patients with benign FMTLE remained classified as benign, 20.7% became refractory and 37.9% were in remission. In the subgroup of FMTLE in remission 21 75% remained without seizures; 21.4% were classified as benign FMTLE, and one died (3.6%) from cause unrelated to epilepsy. All refractory patients remained refractory. From the asymptomatic group, 10.8% became symptomatic (FMTLE). The mean follow up was 76.0 ± 21.2 months. CONCLUSION: Prospective follow up of more than 7 years in patients with FMTLE revealed that it is unlikely to achieve seizure control in those with refractory seizures. Patients with diagnose of more benign forms of FMTLE for more than one year are likely to either remit or remain under well controlled seizures. The majority of patients who had achieved seizure remission remained seizure-free and none became refractory. Asymptomatic individuals had a greater probability to have seizures compared to the general population in a 6 year period of follow up.OBJETIVOS: Analisar a evolução de famílias com epilepsia de lobo temporal mesial familiar (ELTMF). METODOLOGIA: Seguimento prospectivo de 64 pacientes com ELTMF e 37 membros assintomáticos pertencente a 28 famílias. RESULTADOS: A média de seguimento dos pacientes com ELTMF foi de 93,4 ± 15,8 meses. Na avaliação inicial os pacientes foram divididos em benignos (n = 29), remissão (n = 28) e refratários (n = 7). Na última visita disponível, 41,4% dos pacientes com ELTMF benigna permaneceram classificados como benignos, 20,7% tornaram-se refratários e 37,9% entraram em remissão. No grupo em remissão, 75% permaneceram livres de crise, 21,4% foram classificados como benignos e um faleceu (3,6%) de causa não relacionada à epilepsia. Todos pacientes refratários permaneceram refratários. Em relação aos assintomáticos 10,8% evoluíram com crises. A média de seguimento dos assintomáticos foi de 76,0 ± 21,2 meses. CONCLUSÃO: O seguimento prospectivo de mais de 7 anos de pacientes com ELTMF revelou que é improvável ocorrer controle de crises no grupo refratário. No grupo benigno é muito provável que estes indivíduos entrem em remissão ou permaneçam com evolução benigna. A maioria dos pacientes do grupo em remissão permaneceu em remissão e nenhum se tornou refratário. Em relação aos assintomáticos a probabilidade de apresentar uma crise no decorrer de aproximadamente 6 anos foi maior que o observado na população geral.111113Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

The new world of RNAs

One of the major developments that resulted from the human genome sequencing projects was a better understanding of the role of non-coding RNAs (ncRNAs). NcRNAs are divided into several different categories according to size and function; however, one shared feature is that they are not translated into proteins. In this review, we will discuss relevant aspects of ncRNAs, focusing on two main types: i) microRNAs, which negatively regulate gene expression either by translational repression or target mRNA degradation, and ii) small interfering RNAs (siRNAs), which are involved in the biological process of RNA interference (RNAi). Our knowledge regarding these two types of ncRNAs has increased dramatically over the past decade, and they have a great potential to become therapeutic alternatives for a variety of human conditions.28529

Spinocerebellar ataxias: genotype-phenotype correlations in 104 Brazilian families

OBJECTIVE: Spinocerebellar ataxias are neurodegenerative disorders involving the cerebellum and its connections. There are more than 30 distinct subtypes, 16 of which are associated with an identified gene. The aim of the current study was to evaluate a large group of patients from 104 Brazilian families with spinocerebellar ataxias. METHODS: We studied 150 patients from 104 families with spinocerebellar ataxias who had received molecular genetic testing for spinocerebellar ataxia types 1, 2, 3, 6, 7, 8, 10, 12, 17, and dentatorubral-pallidoluysian atrophy. A statistical analysis of the results was performed using basic descriptive statistics and the correlation coefficient (r), Student's t-test, chi-square test, and Yates' correction. The statistical significance level was established for p-value

Exploratory structural assessment in craniocervical dystonia: global and differential analyses

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOOur goal was to investigate the cortical thickness and subcortical volume in subjects with craniocervical dystonia and its subgroups. We studied 49 subjects, 17 with cervical dystonia, 18 with blepharospasm or oromandibular dystonia, and 79 healthy cont128FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2013/13270-62010/11085-92013/07559-