The 'fragile' X chromosome in the Martin-Bell-Renpenning syndrome and in males with other forms of familial mental retardation.

Proops, Rosalyn; Webb, T.

doi:10.1136/jmg.18.5.366

Cited by 43 publications

(18 citation statements)

References 12 publications

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“…Foi constatado que existe associação do autismo com a SXF que, entretanto, é casual e não causal. Não é raro que indivíduos com SXF tenham diagnósticos iniciais de autismo 9 , conforme observado em vários estudos [10][11][12][13][14] .…”

Section: Características Físicas E Comportamentais Na Síndrome Do X Funclassified

Características da comunicação em indivíduos com a síndrome do X frágil

Yonamine

Silva

2002

Arq. Neuro-Psiquiatr.

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RESUMO -O objetivo deste estudo foi, a partir da avaliação de linguagem de um grupo de 10 meninos com idades variando entre 6 e 13 anos e com a síndrome do cromossomo X frágil (SXF), caracterizar o nível de comunicação desses indivíduos a partir de escalas de desenvolvimento normal. Constatou-se que dentro desta amostra, os indivíduos apresentaram predominantemente forma de comunicação linguística (80%), atingindo o nível máximo de até 3 anos de idade. Concluiu-se que os dados obtidos confirmam o significativo atraso na aquisição e desenvolvimento da comunicação, necessitando, portanto, de intervenção precoce e especializada.PALAVRAS-CHAVE: síndrome do X frágil, fala, linguagem, comunicação. Characteristics of the communication in individuals with fragile X syndromeABSTRACT -The aim of this study was to make a characterization of the communication in a group with fragile X syndrome (FXS), based on normal development scale. The sample has 10 boys, between 6 and 13 years and with FXS. All of them were submitted to language evaluation. The most part of them had the communication in linguistic form (80%), until 3 years old. It was considered that the data confirmed the significant delay in the acquisition and development of the communication, being necessary an early and specialized intervention.

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Section: Características Físicas E Comportamentais Na Síndrome Do X Funclassified

Características da comunicação em indivíduos com a síndrome do X frágil

Yonamine

Silva

2002

Arq. Neuro-Psiquiatr.

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“…All of the repeats associated with the Repeat Expansion Diseases form secondary structures that are thought to play a role in expansion and in some cases these secondary structures are also thought to be responsible for the underlying pathology [7] Those Repeat Expansion Diseases resulting from expansion of CGG/CCG-repeat tracts, such as Fragile X syndrome (FXS), are also associated with the expression of a fragile site coincident with the repeat [8–12]. Fragile sites are often characterized as chromosomal regions with constrictions, gaps or breaks that are visible during metaphase in cells grown in the presence of specific chemical inducers (reviewed in [13]).…”

Section: Introductionmentioning

confidence: 99%

Evidence for chromosome fragility at the frataxin locus in Friedreich ataxia

Kumari

Hayward

Nakamura

et al. 2015

Mutation Research/Fundamental and Molecular Mechanisms of Mutag

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Friedreich ataxia (FRDA) is a member of the Repeat Expansion Diseases, a group of genetic conditions resulting from an increase/expansion in the size of a specific tandem array. FRDA results from expansion of a GAA/TTC-tract in the first intron of the frataxin gene (FXN). The disease-associated tandem repeats all form secondary structures that are thought to contribute to the propensity of the repeat to expand. The subset of these diseases that result from a CGG/CCG-repeat expansion, such as Fragile X syndrome, also express a folate-sensitive fragile site coincident with the repeat on the affected chromosome. This chromosome fragility involves the generation of chromosome/chromatid gaps or breaks, or the high frequency loss of one or both copies of the affected gene when cells are grown underfolate stress or as we showed previously, in the presence of an inhibitor of the ATM checkpoint kinase. Whether Repeat Expansion Disease loci containing different repeats form similar fragile sites was not known. We show here that the region of chromosome 9 that contains the FXN locus is intrinsically prone to breakage in vivo even in control cells. However, like FXS alleles, FRDA alleles show significantly elevated levels of chromosome abnormalities in the presence of an ATM inhibitor, consistent with the formation of a fragile site.

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“…The FXDs are named for a folate-sensitive fragile site (FS), a gap or constriction of the chromatin, coincident with the FMR1 gene [7, 8]. This site only becomes apparent when the repeat number exceeds 200.…”

Section: Introductionmentioning

confidence: 99%

Chromatin changes in the development and pathology of the Fragile X-associated disorders and Friedreich ataxia

Kumari

Lokanga

Yudkin

et al. 2012

Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanism

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The Fragile X-associated disorders (FXDs) and Friedeich ataxia (FRDA) are genetic conditions resulting from expansion of a trinucleotide repeat in a region of the affected gene that is transcribed but not translated. In the case of the FXDs, pathology results from expansion of CGG•CCG-repeat tract in the 5′ UTR of the FMR1 gene, while pathology in FRDA results from expansion of a GAA•TTC-repeat in intron 1 of the FXN gene. Expansion occurs during gametogenesis or early embryogenesis by a mechanism that is not well understood. Expansion then produces disease pathology in various ways that are not completely understood either. In the case of the FXDs, alleles with 55–200 repeats express higher than normal levels of a transcript that is thought to be toxic, while alleles with >200 repeats are silenced. In addition, alleles with >200 repeats are associated with a cytogenetic abnormality known as a fragile site, which is apparent as a constriction or gap in the chromatin that is seen when cells are grown in presence of inhibitors of thymidylate synthase. FRDA alleles show a deficit of the FXN transcript. This review will address the role of repeat-mediated chromatin changes in these aspects of FXD and FRDA disease pathology.

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The 'fragile' X chromosome in the Martin-Bell-Renpenning syndrome and in males with other forms of familial mental retardation.

Cited by 43 publications

References 12 publications

Características da comunicação em indivíduos com a síndrome do X frágil

Características da comunicação em indivíduos com a síndrome do X frágil

Evidence for chromosome fragility at the frataxin locus in Friedreich ataxia

Chromatin changes in the development and pathology of the Fragile X-associated disorders and Friedreich ataxia

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