RESUMO
Patients with unbalanced X-autosome translocations are rare and usually present a skewed X-chromosome inactivation (XCI) pattern, with the derivative chromosome being preferentially inactivated, and with a possible spread of XCI into the autosomal regions attached to it, which can inactivate autosomal genes and affect the patients' phenotype. We describe three patients carrying different unbalanced X-autosome translocations, confirmed by G-banding karyotype and array techniques. We analyzed their XCI pattern and inactivation spread into autosomal regions, through HUMARA, ZDHHC15 gene assay and the novel 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, and identified an extremely skewed XCI pattern toward the derivative chromosomes for all the patients, and a variable pattern of late-replication on the autosomal regions of the derivative chromosomes. All patients showed phenotypical overlap with patients presenting deletions of the autosomal late-replicating regions, suggesting that the inactivation of autosomal segments may be responsible for their phenotype. Our data highlight the importance of the XCI spread into autosomal regions for establishing the clinical picture in patients carrying unbalanced X-autosome translocations, and the incorporation of EdU as a novel and precise tool to evaluate the inactivation status in such patients.
Assuntos
Transtornos Cromossômicos/diagnóstico , Transtornos Cromossômicos/genética , Cromossomos , Estudos de Associação Genética , Fenótipo , Translocação Genética , Inativação do Cromossomo X , Hibridização Genômica Comparativa , Análise Citogenética , Replicação do DNA , Proteínas de Ligação a DNA/genética , Evolução Molecular , Humanos , Hibridização in Situ Fluorescente , Receptores Androgênicos/genéticaRESUMO
Duplication of the short arm of chromosome 12 is a rare chromosomal abnormality that may arise de novo or result from malsegregation of a balanced parental translocation. This study comprises the clinical description, cytogenetic and cytogenomic analyses and genotype-phenotype correlation in a patient with facial dysmorphism, developmental delay and intellectual impairment caused by non-mosaic partial duplication and a paracentric inversion 12p. The patient's GTG-banded karyotype was 46,XX,invdup(12)(pter â p13.32::p11.1 â p13.31::p13.31 â qter). A genetic gain of approximately 28 Mb was detected in the chromosomal region arr[GRCh37]12p13.31-p11.1(6914072_34756209)x3. The chromosomal alteration seen in our patient is described as "pure" partial duplication 12p. In most cases, duplication 12p phenotype is characterized by dysmorphic features, multiple congenital anomalies and intellectual disability. A small number of cases in literature have described genes associated with neurodevelopmental disease, such as ING4, CHD4, MFAP5, GRIN2B, SOX5, SCN8A and PIANP. In our patient the duplication 12p was de novo. This study should contribute to the genotype-phenotype correlation in partial duplication 12p cases.
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X-chromosome inactivation occurs randomly in normal female cells. However, the inactivation can be skewed in patients with alterations in X-chromosome. In balanced X-autosome translocations, normal X is preferentially inactivated, while in unbalanced X alterations, the aberrant X is usually inactivated. Here, we present a novel strategy to verify the skewed X inactivation pattern through the incorporation of 5-ethynyl-2'-deoxyuridine (EdU) into cells, in 11 patients: five carriers of balanced X-autosome translocations and six of unbalanced X-chromosome alterations. Since EdU is a labeled nucleoside analog of thymidine, its incorporation during DNA synthesis can reveal late replication regions and the inactive X-chromosome. All EdU findings were validated by the human androgen receptor gene (HUMARA) assay. The late replication regions were easily and quickly visualized in all cells, where inactive Xs are marked with strong green fluorescence. It was observed that the normal X-chromosome was preferentially inactivated in patients with balanced X-autosome translocations; while the aberrant X-chromosome was inactivated in most cells from patients with unbalanced alterations. By performing the fluorescence-based EdU assay, the differences between the active and inactive X-chromosomes are more easily recognizable than by classic cytogenetic methods. Furthermore, EdU incorporation allows the observation of the late replication regions in autosomal segments present in X derivatives from X-autosome translocations. Therefore, EdU assay permits an accurate and efficient cytogenetic evaluation of the X inactivation pattern with a low-cost, easy to perform and highly reproducible technique.
Assuntos
Cromossomos Humanos X/genética , Desoxiuridina/análogos & derivados , Rearranjo Gênico , Inativação do Cromossomo X , Transtornos Cromossômicos/genética , Análise Citogenética , Replicação do DNA , Desoxiuridina/metabolismo , Feminino , Humanos , Masculino , Translocação GenéticaRESUMO
Resumo:OBJETIVO:caracterizar e comparar a frequência das disfluências da fala de adultos com gagueira desenvolvimental persistente familial do sexo masculino e feminino, a severidade do distúrbio e determinar a prevalência familial e a razão entre gêneros da gagueira nos familiares dos probandos.MÉTODOS:participaram 30 adultos com gagueira (18 a 53 anos), divididos em dois grupos, sendo 20 do sexo masculino e 10 do sexo feminino. Os procedimentos realizados foram: história clínica e familial, avaliação da fluência e Instrumento de Severidade da Gagueira.RESULTADOS:as porcentagens de disfluências típicas da gagueira (p=0,352), de outras disfluências (p=0,947) e do total das disfluências (p=0,522) foram semelhantes entre os grupos masculino e feminino. A média de disfluências típicas da gagueira foi 5,23% e de outras disfluências 5,50%. O subtipo leve foi manifestado pela maioria dos participantes (83,3%). Os familiares do gênero masculino apresentaram maior risco de apresentar gagueira (p<0,001). Do total de 1002 familiares, 85 apresentaram gagueira. No total de familiares afetados (n=85), 53 eram do sexo masculino e 32 do feminino.CONCLUSÃO:não houve diferenças entre os grupos masculino e feminino nas medidas analisadas. Quanto à frequência das disfluências, aproximadamente metade do total das disfluências foi caracterizada como disfluências típicas da gagueira. O subtipo de gagueira desenvolvimental persistente familial foi caracterizado principalmente por um distúrbio classificado quanto à severidade como leve. O risco dos familiares dos probandos afetados foi de 8,5%. A gagueira afetou mais pessoas do gênero masculino em relação ao feminino, numa proporção de 3,72:1.
Abstract:PURPOSE:to characterize and to compare the frequency of speech disfluency in adults with familial persistent developmental stuttering in males and females, the stuttering severity and then to determinate the familial prevalence and the sexual ratio of stuttering among the families members of the probands.METHODS:participants were 30 adults who stutter (ages between 18 and 53 years old), divided in two groups: one with 20 males, and the other with 10 females. Data were gathered by clinical and familial history, fluency assessment and Stuttering Severity Instrument.RESULTS:the percentages of stuttering-like disfluencies (SLD) (p=0.352), of other disfluencies (OD) (p=0.947) and of total disfluencies (TD) (p=0.522) were similar between the males and females. The participants showed a mean of 5.23% of SLD and 5.5% of OD. The mild subgroup was the prevalent among the participants (83.3%). The male families' members showed greater risk to stutter when compared to the females (p<0.001). The results of 1002 families' members showed 85 familiars with stuttering, which 53 were male and 32 female.CONCLUSIONS:there were no differences between the males and females concerning to the analyzed measures. Regarding the frequency of disfluencies the results show that around a half of total disfluencies was characterized as SLD. The subgroup of familial persistent developmental stuttering was characterized mainly as mild. The risk among relatives of affected probands was 8.5%.The familial prevalence data showed that risk that a person have to manifest stuttering when there is some familial affected was 8.5%.The sexual ratio showed stuttering affecting mainly males than females, and was 3.72:1.
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Detailed molecular characterization of chromosomal rearrangements involving X-chromosome has been a key strategy in identifying X-linked intellectual disability-causing genes. We fine-mapped the breakpoints in four women with balanced X-autosome translocations and variable phenotypes, in order to investigate the corresponding genetic contribution to intellectual disability. We addressed the impact of the gene interruptions in transcription and discussed the consequences of their functional impairment in neurodevelopment. Three patients presented with cognitive impairment, reinforcing the association between the disrupted genes (TSPAN7-MRX58, KIAA2022-MRX98, and IL1RAPL1-MRX21/34) and intellectual disability. While gene expression analysis showed absence of TSPAN7 and KIAA2022 expression in the patients, the unexpected expression of IL1RAPL1 suggested a fusion transcript ZNF611-IL1RAPL1 under the control of the ZNF611 promoter, gene disrupted at the autosomal breakpoint. The X-chromosomal breakpoint definition in the fourth patient, a woman with normal intellectual abilities, revealed disruption of the ZDHHC15 gene (MRX91). The expression assays did not detect ZDHHC15 gene expression in the patient, thus questioning its involvement in intellectual disability. Revealing the disruption of an X-linked intellectual disability-related gene in patients with balanced X-autosome translocation is a useful tool for a better characterization of critical genes in neurodevelopment. © 2015 Wiley Periodicals, Inc.
Assuntos
Deficiência Intelectual Ligada ao Cromossomo X/genética , Translocação Genética , Adolescente , Adulto , Criança , Mapeamento Cromossômico , Feminino , Genes Ligados ao Cromossomo X , Humanos , Hibridização in Situ FluorescenteRESUMO
Sotos syndrome (SoS) is a multiple anomaly, congenital disorder characterized by overgrowth, macrocephaly, distinctive facial features and variable degree of intellectual disability. Haploinsufficiency of the NSD1 gene at 5q35.3, arising from 5q35 microdeletions, point mutations, and partial gene deletions, accounts for a majority of patients with SoS. Recently, mutations and possible pathogenetic rare CNVs, both affecting a few candidate genes for overgrowth, have been reported in patients with Sotos-like overgrowth features. To estimate the frequency of NSD1 defects in the Brazilian SoS population and possibly reveal other genes implicated in the etiopathogenesis of this syndrome, we collected a cohort of 21 Brazilian patients, who fulfilled the diagnostic criteria for SoS, and analyzed the NSD1 and PTEN genes by means of multiplex ligation-dependent probe amplification and mutational screening analyses. We identified a classical NSD1 microdeletion, a novel missense mutation (p.C1593W), and 2 previously reported truncating mutations: p.R1984X and p.V1760Gfs*2. In addition, we identified a novel de novo PTEN gene mutation (p.D312Rfs*2) in a patient with a less severe presentation of SoS phenotype, which did not include pre- and postnatal overgrowth. For the first time, our study implies PTEN in the pathogenesis of SoS and further emphasizes the existence of ethno-geographical differences in NSD1 molecular alterations between patients with SoS from Europe/North America (70-93%) and those from South America (10-19%).
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A síndrome de Down é uma condição na qual os indivíduos apresentam comprometimento intelectual e alterações de linguagem oral. A disfluência de fala está presente tanto durante a conversa espontânea como em produções orais de narrativas direcionadas. Este estudo teve como principal objetivo revisar a literatura sobre a disfluência e a narrativa em indivíduos com a síndrome de Down, publicada entre 2002 e 2012, em bases de dados eletrônicos. Foram encontrados 17 artigos e selecionados oito, de acordo com os critérios de inclusão e exclusão. Destes, dois discorriam especificamente sobre a disfluência na síndrome de Down, e seis sobre a narrativa nesta população. A deficiência intelectual é parte do fenótipo dos indivíduos com SD e, em decorrência do comprometimento intelectual, prejuízos na aquisição e no desenvolvimento da linguagem. Estudos específicos, principalmente sobre a fluência/disfluência; e, sobre o desempenho na tarefa da narrativa, ainda são escassos e inconclusivos. A disfluência não aparece na maioria das descrições do fenótipo de linguagem dos indivíduos com esta condição, que mereceria, estudos clínicos adicionais.
Down’s syndrome is a condition in which individuals have intellectual impairment and oral language disorders. Speech disfluency is present during both spontaneous conversations as in productions of directed oral narratives. This study aimed to review the published literature between 2002 and 2012 in eletronic databases on disfluency and narrative in individuals with Down syndrome. There were 17 articles and eight were selected according to the criteria of inclusion and exclusion. Two of these articles specifically discoursed on dysfluency in Down’s syndrome and the other six on the narrative in this population. Intellectual disability is part of the phenotype of individuals with DS and, as a result of the intellectual impairment, losses occur on the acquisition and development of language. Specific studies about, mainly on fluency/disfluency, and the performance on a task of narrative and, are still scarce and inconclusive. Disfluency doesn’t appear in most descriptions of the language phenotype of individuals with this condition, which would deserve additional clinical studies.
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A number of speech disorders including stuttering have been shown to have important genetic contributions, as indicated by high heritability estimates from twin and other studies. We studied the potential contribution to stuttering from variants in the FOXP2 gene, which have previously been associated with developmental verbal dyspraxia, and from variants in the CNTNAP2 gene, which have been associated with specific language impairment (SLI). DNA sequence analysis of these two genes in a group of 602 unrelated cases, all with familial persistent developmental stuttering, revealed no excess of potentially deleterious coding sequence variants in the cases compared to a matched group of 487 well characterized neurologically normal controls. This was compared to the distribution of variants in the GNPTAB, GNPTG, and NAGPA genes which have previously been associated with persistent stuttering. Using an expanded subject data set, we again found that NAGPA showed significantly different mutation frequencies in North Americans of European descent (p=0.0091) and a significant difference existed in the mutation frequency of GNPTAB in Brazilians (p=0.00050). No significant differences in mutation frequency in the FOXP2 and CNTNAP2 genes were observed between cases and controls. To examine the pattern of expression of these five genes in the human brain, real time quantitative reverse transcription PCR was performed on RNA purified from 27 different human brain regions. The expression patterns of FOXP2 and CNTNAP2 were generally different from those of GNPTAB, GNPTG and NAPGA in terms of relatively lower expression in the cerebellum. This study provides an improved estimate of the contribution of mutations in GNPTAB, GNPTG and NAGPA to persistent stuttering, and suggests that variants in FOXP2 and CNTNAP2 are not involved in the genesis of familial persistent stuttering. This, together with the different brain expression patterns of GNPTAB, GNPTG, and NAGPA compared to that of FOXP2 and CNTNAP2, suggests that the genetic neuropathological origins of stuttering differ from those of verbal dyspraxia and SLI.
Assuntos
Encéfalo/metabolismo , Fatores de Transcrição Forkhead/genética , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Gagueira/genética , Gagueira/metabolismo , Adulto , Brasil , Criança , Pré-Escolar , Feminino , Fatores de Transcrição Forkhead/metabolismo , Expressão Gênica , Humanos , Lactente , Recém-Nascido , Masculino , Proteínas de Membrana/metabolismo , Análise em Microsséries , Pessoa de Meia-Idade , Mutação , Proteínas do Tecido Nervoso/metabolismo , América do Norte , Diester Fosfórico Hidrolases/genética , Diester Fosfórico Hidrolases/metabolismo , Transferases (Outros Grupos de Fosfato Substituídos)/genética , Transferases (Outros Grupos de Fosfato Substituídos)/metabolismo , População Branca/genética , Adulto JovemRESUMO
BACKGROUND: Several countries have implemented mandatory folic acid fortification of wheat flour and selected grain products to increase the folate intake of reproductive-aged women. Brazil implemented a folic acid fortification program in 2004. No previous studies have examined folate differences among Brazilian women following the mandate. OBJECTIVE: We evaluate differences in serum and red blood cell (RBC) folate concentrations between two samples of women of childbearing age from selective communities in Brazil, one tested before (N = 116) and the other after the mandate (N = 240). METHODS: We compared the baseline folate levels of women enrolled in a prevention study shortly before the fortification mandate was implemented, to baseline levels of women from the same communities enrolled in the same study shortly after fortification began. The participants were women enrolled in a folate supplementation clinical trial, at a hospital specializing in treating craniofacial anomalies in the city of Bauru from January 29, 2004 to April 27, 2005. We only compared baseline folate levels before the women received oral cleft prevention program (OCPP) folic acid supplements. RESULTS: Women enrolled after the fortification mandate had higher means of serum folate (20.3 versus 11.2 nmol/L; p < 0.001) and RBC folate (368.3 versus 177.6 nmol/L; p < 0.001) than women enrolled before the mandate. Differences in folate levels between the two groups remained after adjusting for several co-variables. CONCLUSIONS: The results suggest that serum and RBC folate levels among women of childbearing age increased after implementing the folic acid fortification mandate in Brazil.
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Ácido Fólico/sangue , Ácido Fólico/farmacologia , Alimentos Fortificados , Adulto , Brasil , Relação Dose-Resposta a Droga , Feminino , Ácido Fólico/administração & dosagem , Humanos , Adulto JovemRESUMO
CONTEXT: Robertsonian translocations (RT) are among the most common balanced structural rearrangements in humans and comprise complete chromatin fusion of the long arm of two acrocentric chromosomes. Nevertheless, non-Robertsonian translocation involving these chromosomes is a rare event. CASE REPORT: We report a de novo unbalanced translocation involving chromosomes 15 and 21. The newborn was the daughter of a 29-year-old mother and a 42-year-old father. The couple was non-consanguineous. Clinical findings led to the diagnosis of Down syndrome (DS) with severe congenital heart defects (persistent arterial duct, and complete atrioventricular septal defect), as well as low birth length and weight (< 5th and < 10th percentile, respectively, based on specific measurement curves for DS). Conventional cytogenetic analysis revealed the karyotype 46,XX,der(15)(15pter â 15q26.2::21q11.2 â 21 qter). The translocation was confirmed by means of fluorescence in situ hybridization. The parents had normal karyotypes. CONCLUSIONS: Differently from RT, in our case a rare event occurred involving the distal segment of 15q and the proximal segment of 21q. Only two reports of this translocation, involving chromosomes 15 and 21 but different breakpoints, have been described so far. The association between 21q duplication and 15q deletion makes it difficult to separate the effect of each chromosome, but might also be responsible for increasing the growth retardation, as detected in our case. Cytogenetic analysis on DS patients is mandatory not only to confirm the diagnosis, but also to assess the risk of recurrence at genetic counseling, as well as to evaluate the contribution of other chromosome aberrations in the final phenotype.