Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Thyroid ; 28(7): 891-901, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29897006

RESUMO

BACKGROUND: Euthyroid multinodular goiter (MNG) is common, but little is known about the genetic variations conferring predisposition. Previously, a family with MNG of adolescent onset was reported in which some family members developed papillary thyroid carcinomas (PTC). METHODS: Genome-wide linkage analysis and next-generation sequencing were conducted to identify genetic variants that may confer disease predisposition. A multipoint nonparametric LOD score of 3.01 was obtained, covering 19 cM on chromosome 20p. Haplotype analysis reduced the region of interest to 10 cM. RESULTS: Analysis of copy number variation identified an intronic InDel (∼1000 bp) in the PLCB1 gene in all eight affected family members and carriers (an unaffected person who has inherited the genetic trait). This InDel is present in approximately 1% of "healthy" Caucasians. Next-generation sequencing of the region identified no additional disease-associated variant, suggesting a possible role of the InDel. Since PLCB1 contributes to thyrocyte growth regulation, the InDel was investigated in relevant Caucasian cohorts. It was detected in 0/70 PTC but 4/81 unrelated subjects with MNG (three females; age at thyroidectomy 27-59 years; no family history of MNG/PTC). The InDel frequency is significantly higher in MNG subjects compared to controls (χ2 = 5.076; p = 0.024. PLCB1 transcript levels were significantly higher in thyroids with the InDel than without (p < 0.02). CONCLUSIONS: The intronic PLCB1 InDel is the first variant found in familial multiple papilloid adenomata-type MNG and in a subset of patients with sporadic MNG. It may function through overexpression, and increased PLC activity has been reported in thyroid neoplasms. The potential role of the deletion as a biomarker to identify MNG patients more likely to progress to PTC merits exploration.

3.
Am J Med Genet B Neuropsychiatr Genet ; 177(3): 369-376, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29418072

RESUMO

Multiple genome-wide association studies of schizophrenia have implicated genetic variants within the gene encoding microRNA-137. As risk variants within or regulated by MIR137 have been implicated in memory performance, we investigated the additive effects of schizophrenia-associated risk variants in genes empirically regulated by MIR137 on brain regions associated with memory function. A polygenic risk score (PRS) was calculated (at a p = 0.05 threshold), using this empirically regulated MIR137 gene set, to investigate associations between this PRS and structural brain measures. These measures included total brain volume, cortical thickness, cortical surface area, and hippocampal volume, in a sample of 216 individuals consisting of healthy participants (n = 171) and patients with psychosis (n = 45). We did not observe a significant association between MIR137 PRS and these cortical thickness, surface area or hippocampal volume measures linked to memory function; a significant association between increasing PRS and decreasing total brain volume, independent of diagnosis status (R2 = 0.008, Beta = -0.09, p = 0.029), was observed. This did not survive correction for multiple testing. In conclusion, our study yielded only suggestive evidence that risk variants interacting with MIR137 impacts on cortical structure.

4.
Nat Genet ; 50(3): 381-389, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29483656

RESUMO

Schizophrenia is a debilitating psychiatric condition often associated with poor quality of life and decreased life expectancy. Lack of progress in improving treatment outcomes has been attributed to limited knowledge of the underlying biology, although large-scale genomic studies have begun to provide insights. We report a new genome-wide association study of schizophrenia (11,260 cases and 24,542 controls), and through meta-analysis with existing data we identify 50 novel associated loci and 145 loci in total. Through integrating genomic fine-mapping with brain expression and chromosome conformation data, we identify candidate causal genes within 33 loci. We also show for the first time that the common variant association signal is highly enriched among genes that are under strong selective pressures. These findings provide new insights into the biology and genetic architecture of schizophrenia, highlight the importance of mutation-intolerant genes and suggest a mechanism by which common risk variants persist in the population.

5.
Neuropsychopharmacology ; 42(13): 2612-2622, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28607492

RESUMO

With >100 common variants associated with schizophrenia risk, establishing their biological significance is a priority. We sought to establish cognitive effects of risk variants at loci implicated in synaptic transmission by (1) identifying GWAS schizophrenia variants whose associated gene function is related to synaptic transmission, and (2) testing for association between these and measures of neurocognitive function. We selected variants, reported in the largest GWAS to date, associated with genes involved in synaptic transmission. Associations between genotype and cognitive test score were analyzed in a discovery sample (988 Irish participants, including 798 with psychosis), and replication samples (528 UK patients with schizophrenia/schizoaffective disorder; 921 German participants including 362 patients with schizophrenia). Three loci showed significant associations with neuropsychological performance in the discovery samples. This included an association between the rs2007044 (risk allele G) within CACNA1C and poorer working memory performance (increased errors B (95% CI)=0.635-4.535, p=0.012), an effect driven mainly by the psychosis groups. In an fMRI analysis of working memory performance (n=84 healthy participants, a subset of the discovery sample), we further found evidence that the same CACNA1C allele was associated with decreased functional connectivity between the right dorsolateral prefrontal cortex and right superior occipital gyrus/cuneus and anterior cingulate cortex. In conclusion, these data provide evidence to suggest that the CACNA1C risk variant rs2007044 is associated with poorer memory function that may result from risk carriers' difficulty with top-down initiated responses caused by dysconnectivity between the right DLPFC and several cortical regions.


Assuntos
Canais de Cálcio Tipo L/genética , Cognição , Predisposição Genética para Doença , Memória de Curto Prazo , Esquizofrenia/genética , Transmissão Sináptica/genética , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Mapeamento Encefálico , Feminino , Loci Gênicos , Estudo de Associação Genômica Ampla , Humanos , Imagem por Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Testes Neuropsicológicos , Polimorfismo de Nucleotídeo Único , Transtornos Psicóticos/genética
6.
Eur Arch Psychiatry Clin Neurosci ; 267(6): 527-539, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27552816

RESUMO

Increased reactivity to stress is observed in patients with schizophrenia spectrum disorders and their healthy siblings in comparison with the general population. Additionally, higher levels of neuroticism, as a proposed psychological measure of stress sensitivity, increase the risk of schizophrenia. HPA axis dysregulation is one of the possible mechanisms related to the vulnerability-stress model of schizophrenia, and recent studies revealed a possible role of the functional genetic variants of FK506-binding protein 51 (FKBP5) gene which modulate activity of HPA axis. The purpose of the present study was to investigate impact of FKBP5 on schizophrenia in Serbian patients and to explore relationship between genetic variants and neuroticism by using the case-sibling-control design. In 158 subjects, we measured psychotic experiences, childhood trauma and neuroticism. Nine single-nucleotide polymorphisms (rs9295158, rs3800373, rs9740080, rs737054, rs6926133, rs9380529, rs9394314, rs2766533 and rs12200498) were genotyped. The genetic influence was modeled using logistic regression, and the relationship between genetic variants and neuroticism was assessed by linear mixed model. Our results revealed genetic main effect of FKBP5 risk alleles (A allele of rs9296158 and T allele of rs3800373) and AGTC "risk" haplotype combination (rs9296158, rs3800373, rs9470080 and rs737054, respectively) on schizophrenia, particularly when childhood trauma was set as a confounding factor. We confirmed strong relationship between neuroticism and psychotic experiences in patients and siblings and further showed relationship between higher levels of neuroticism and FKBP5 risk variants suggesting potential link between biological and psychosocial risk factors. Our data support previous findings that trauma exposure shapes FKBP5 impact on schizophrenia.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância , Interação Gene-Ambiente , Neuroticismo , Transtornos Psicóticos/etiologia , Transtornos Psicóticos/genética , Esquizofrenia/etiologia , Esquizofrenia/genética , Irmãos , Estresse Psicológico/complicações , Proteínas de Ligação a Tacrolimo/genética , Adulto , Estudos de Casos e Controles , Suscetibilidade a Doenças , Feminino , Humanos , Masculino , Modelos Teóricos , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Sérvia , Adulto Jovem
7.
Am J Med Genet B Neuropsychiatr Genet ; 171(8): 1170-1179, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27762073

RESUMO

Epigenetic mechanisms are an important heritable and dynamic means of regulating various genomic functions, including gene expression, to orchestrate brain development, adult neurogenesis, and synaptic plasticity. These processes when perturbed are thought to contribute to schizophrenia pathophysiology. A core feature of schizophrenia is cognitive dysfunction. For genetic disorders where cognitive impairment is more severe such as intellectual disability, there are a disproportionally high number of genes involved in the epigenetic regulation of gene transcription. Evidence now supports some shared genetic aetiology between schizophrenia and intellectual disability. GWAS have identified 108 chromosomal regions associated with schizophrenia risk that span 350 genes. This study identified genes mapping to those loci that have epigenetic functions, and tested the risk alleles defining those loci for association with cognitive deficits. We developed a list of 350 genes with epigenetic functions and cross-referenced this with the GWAS loci. This identified eight candidate genes: BCL11B, CHD7, EP300, EPC2, GATAD2A, KDM3B, RERE, SATB2. Using a dataset of Irish psychosis cases and controls (n = 1235), the schizophrenia risk SNPs at these loci were tested for effects on IQ, working memory, episodic memory, and attention. Strongest associations were for rs6984242 with both measures of IQ (P = 0.001) and episodic memory (P = 0.007). We link rs6984242 to CHD7 via a long range eQTL. These associations were not replicated in independent samples. Our study highlights that a number of genes mapping to risk loci for schizophrenia may function as epigenetic regulators of gene expression but further studies are required to establish a role for these genes in cognition. © 2016 Wiley Periodicals, Inc.


Assuntos
Transtornos Cognitivos/genética , Epigênese Genética/genética , Esquizofrenia/genética , Adulto , Alelos , Encéfalo/metabolismo , Cognição/fisiologia , Transtornos Cognitivos/psicologia , Epigenômica , Feminino , Regulação da Expressão Gênica/genética , Frequência do Gene , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Irlanda , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Transtornos Psicóticos/genética , Fatores de Risco , Psicologia do Esquizofrênico
8.
BMC Med Genet ; 17(1): 34, 2016 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-27113213

RESUMO

BACKGROUND: Copy number variants (CNVs) have been linked to neurodevelopmental disorders such as intellectual disability (ID), autism, epilepsy and psychiatric disease. There are few studies of CNVs in patients with both ID and epilepsy. METHODS: We evaluated the range of rare CNVs found in 80 Welsh patients with ID or developmental delay (DD), and childhood-onset epilepsy. We performed molecular cytogenetic testing by single nucleotide polymorphism array or microarray-based comparative genome hybridisation. RESULTS: 8.8 % (7/80) of the patients had at least one rare CNVs that was considered to be pathogenic or likely pathogenic. The CNVs involved known disease genes (EHMT1, MBD5 and SCN1A) and imbalances in genomic regions associated with neurodevelopmental disorders (16p11.2, 16p13.11 and 2q13). Prompted by the observation of two deletions disrupting SCN1A we undertook further testing of this gene in selected patients. This led to the identification of four pathogenic SCN1A mutations in our cohort. CONCLUSIONS: We identified five rare de novo deletions and confirmed the clinical utility of array analysis in patients with ID/DD and childhood-onset epilepsy. This report adds to our clinical understanding of these rare genomic disorders and highlights SCN1A mutations as a cause of ID and epilepsy, which can easily be overlooked in adults.


Assuntos
Variações do Número de Cópias de DNA , Epilepsia/genética , Deficiência Intelectual/genética , Canal de Sódio Disparado por Voltagem NAV1.1/genética , Deleção de Sequência , Adolescente , Adulto , Idade de Início , Criança , Pré-Escolar , Hibridização Genômica Comparativa , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , País de Gales , Adulto Jovem
9.
Lancet Neurol ; 15(6): 585-96, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27017469

RESUMO

BACKGROUND: Parkinson's disease has been reported in a small number of patients with chromosome 22q11.2 deletion syndrome. In this study, we screened a series of large, independent Parkinson's disease case-control studies for deletions at 22q11.2. METHODS: We used data on deletions spanning the 22q11.2 locus from four independent case-control Parkinson's disease studies (UK Wellcome Trust Case Control Consortium 2, Dutch Parkinson's Disease Genetics Consortium, US National Institute on Aging, and International Parkinson's Disease Genomics Consortium studies), which were independent of the original reports of chromosome 22q11.2 deletion syndrome. We did case-control association analysis to compare the proportion of 22q11.2 deletions found, using the Fisher's exact test for the independent case-control studies and the Mantel-Haenszel test for the meta-analyses. We retrieved clinical details of patients with Parkinson's disease who had 22q11.2 deletions from the medical records of these patients. FINDINGS: We included array-based copy number variation data from 9387 patients with Parkinson's disease and 13 863 controls. Eight patients with Parkinson's disease and none of the controls had 22q11.2 deletions (p=0·00082). In the 8451 patients for whom age at onset data were available, deletions at 22q11.2 were associated with Parkinson's disease age at onset (Mann-Whitney U test p=0·001). Age at onset of Parkinson's disease was lower in patients carrying a 22q11.2 deletion (median 37 years, 95% CI 32·0-55·5; mean 42·1 years [SD 11·9]) than in those who did not carry a deletion (median 61 years, 95% CI 60·5-61·0; mean 60·3 years [SD 12·8]). A 22q11.2 deletion was present in more patients with early-onset (p<0·0001) and late-onset Parkinson's disease (p=0·016) than in controls, and in more patients with early-onset than late-onset Parkinson's disease (p=0·005). INTERPRETATION: Clinicians should be alert to the possibility of 22q11.2 deletions in patients with Parkinson's disease who have early presentation or features associated with the chromosome 22q11.2 deletion syndrome, or both. FUNDING: UK Medical Research Council, UK Wellcome Trust, Parkinson's UK, Patrick Berthoud Trust, National Institutes of Health, "Investissements d'Avenir" ANR-10-IAIHU-06, Dutch Parkinson Foundation (Parkinson Vereniging), Neuroscience Campus Amsterdam, National Institute for Health Research, National Institute on Aging, National Institutes of Health.


Assuntos
Síndrome de DiGeorge/genética , Estudo de Associação Genômica Ampla , Doença de Parkinson/genética , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Variações do Número de Cópias de DNA , Síndrome de DiGeorge/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/epidemiologia
10.
Hum Brain Mapp ; 37(2): 491-500, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26510167

RESUMO

A substantial proportion of schizophrenia liability can be explained by additive genetic factors. Risk profile scores (RPS) directly index risk using a summated total of common risk variants weighted by their effect. Previous studies suggest that schizophrenia RPS predict alterations to neural networks that support working memory and verbal fluency. In this study, we apply schizophrenia RPS to fMRI data to elucidate the effects of polygenic risk on functional brain networks during a probabilistic-learning neuroimaging paradigm. The neural networks recruited during this paradigm have previously been shown to be altered to unmedicated schizophrenia patients and relatives of schizophrenia patients, which may reflect genetic susceptibility. We created schizophrenia RPS using summary data from the Psychiatric Genetic Consortium (Schizophrenia Working Group) for 83 healthy individuals and explore associations between schizophrenia RPS and blood oxygen level dependency (BOLD) during periods of choice behavior (switch-stay) and reflection upon choice outcome (reward-punishment). We show that schizophrenia RPS is associated with alterations in the frontal pole (PWHOLE-BRAIN-CORRECTED  = 0.048) and the ventral striatum (PROI-CORRECTED  = 0.036), during choice behavior, but not choice outcome. We suggest that the common risk variants that increase susceptibility to schizophrenia can be associated with alterations in the neural circuitry that support the processing of changing reward contingencies. Hum Brain Mapp 37:491-500, 2016. © 2015 Wiley Periodicals, Inc.


Assuntos
Encéfalo/fisiopatologia , Predisposição Genética para Doença , Aprendizagem por Probabilidade , Esquizofrenia/genética , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Adulto , Circulação Cerebrovascular/fisiologia , Tomada de Decisões/fisiologia , Feminino , Variação Genética , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Oxigênio/sangue , Recompensa , Percepção Visual/fisiologia , Adulto Jovem
11.
Neuroimage Clin ; 7: 764-70, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25844328

RESUMO

Polygenic risk scores, based on risk variants identified in genome-wide-association-studies (GWAS), explain a considerable portion of the heritability for schizophrenia (SZ) and bipolar disorder (BD). However, little is known about the combined effects of these variants, although polygenic neuroimaging has developed into a powerful tool of translational neuroscience. In this study, we used genome wide significant SZ risk variants to test the predictive capacity of the polygenic model and explored potential associations with white matter volume, a key candidate in imaging phenotype for psychotic disorders. By calculating the combined additive schizophrenia risk of seven SNPs (significant hits from a recent schizophrenia GWAS study), we show that increased additive genetic risk for SZ was associated with reduced white matter volume in a group of participants (n = 94) consisting of healthy individuals, SZ first-degree relatives, SZ patients and BD patients. This effect was also seen in a second independent sample of healthy individuals (n = 89). We suggest that a moderate portion of variance (~4%) of white matter volume can be explained by the seven hits from the recent schizophrenia GWAS. These results provide evidence for associations between cumulative genetic risk for schizophrenia and intermediate neuroimaging phenotypes in models of psychosis. Our work contributes to a growing body of literature suggesting that polygenic risk may help to explain white matter alterations associated with familial risk for psychosis.


Assuntos
Encéfalo/patologia , Transtornos Psicóticos/patologia , Esquizofrenia/patologia , Substância Branca/patologia , Idoso , Estudos de Coortes , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Transtornos Psicóticos/genética , Fatores de Risco , Esquizofrenia/genética
12.
Neuroimage ; 116: 207-13, 2015 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-25896933

RESUMO

Increased intra-subject variability (ISV) in reaction times (RTs) is a candidate endophenotype for several psychiatric and neurological conditions, including schizophrenia. ISV reflects the degree of variability in RTs and is thought to be an index of the stability of cognition. It is generally assumed to have the same underlying physiological basis across conditions, but recent evidence raises the possibility that the neural underpinnings of ISV vary with aetiology. Combining genetics with single-trial event-related potentials is an ideal method for investigating the neural basis of ISV in groups where ISV may vary for relatively homogenous reasons. Here we examine the association between P3b latency variability and a polymorphism on the ZNF804A gene associated with psychosis. Ninety-one healthy volunteers genotyped for rs1344706, a polymorphism on ZNF804A, had electroencephalographic data recorded while carrying out three n-back tasks. Data were analysed with a single-trial approach and latency variability of the P3b was compared between the AA homozygous risk group (N=30) and C allele carriers (N=61). P3b latencies were more variable for AA carriers than C carriers. Behavioural ISV, however, was not associated with genotype. The increase in neurophysiological variability, unaccompanied by increased behavioural variability, suggests that this risk gene is associated with an attenuated form of an endophenotype associated with the psychosis phenotype. The increase in both stimulus and response-locked variability also contrasts with previous work into attention-deficit hyperactivity disorder, where only response-locked P3b variability was elevated, suggesting that increased ISV may not signify the same underlying processes in all conditions with which it is associated.


Assuntos
Córtex Cerebral/fisiologia , Potencial Evocado P300 , Fatores de Transcrição Kruppel-Like/genética , Desempenho Psicomotor/fisiologia , Transtornos Psicóticos/genética , Tempo de Reação , Adulto , Alelos , Eletroencefalografia , Feminino , Predisposição Genética para Doença , Humanos , Individualidade , Masculino , Fenótipo , Polimorfismo Genético , Fatores de Risco , Adulto Jovem
13.
Alzheimers Dement ; 11(10): 1144-52, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25496871

RESUMO

INTRODUCTION: Genome-wide association studies identify rs11136000 in the CLU gene, which codes for Apolipoprotein J/Clusterin, as a significant risk variant for Alzheimer's disease (AD). However, the mechanisms by which this variant confers susceptibility remain relatively unknown. METHODS: Eighty-five healthy Caucasian participants underwent functional magnetic resonance imaging during a working memory (WM) task and were genotyped for CLU rs11136000/APOE loci. RESULTS: Here we show that young individuals with the CLU rs11136000 risk variant (C) have higher activation levels in memory-related prefrontal and limbic areas during a WM task. We also found subtle reductions in gray matter in the right hippocampal formation in carriers of the risk variant. DISCUSSION: We suggest that this pattern of multimodal imaging results may reflect incipient structural differences and inefficient functional activation. This study supports accumulating evidence suggesting that genetic risk for AD affects the neural networks associated with memory in healthy individuals.


Assuntos
Doença de Alzheimer/genética , Clusterina/genética , Hipocampo/patologia , Memória de Curto Prazo , Rede Nervosa , Adulto , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Adulto Jovem
14.
Lancet ; 376(9750): 1401-8, 2010 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-20888040

RESUMO

BACKGROUND: Large, rare chromosomal deletions and duplications known as copy number variants (CNVs) have been implicated in neurodevelopmental disorders similar to attention-deficit hyperactivity disorder (ADHD). We aimed to establish whether burden of CNVs was increased in ADHD, and to investigate whether identified CNVs were enriched for loci previously identified in autism and schizophrenia. METHODS: We undertook a genome-wide analysis of CNVs in 410 children with ADHD and 1156 unrelated ethnically matched controls from the 1958 British Birth Cohort. Children of white UK origin, aged 5-17 years, who met diagnostic criteria for ADHD or hyperkinetic disorder, but not schizophrenia and autism, were recruited from community child psychiatry and paediatric outpatient clinics. Single nucleotide polymorphisms (SNPs) were genotyped in the ADHD and control groups with two arrays; CNV analysis was limited to SNPs common to both arrays and included only samples with high-quality data. CNVs in the ADHD group were validated with comparative genomic hybridisation. We assessed the genome-wide burden of large (>500 kb), rare (<1% population frequency) CNVs according to the average number of CNVs per sample, with significance assessed via permutation. Locus-specific tests of association were undertaken for test regions defined for all identified CNVs and for 20 loci implicated in autism or schizophrenia. Findings were replicated in 825 Icelandic patients with ADHD and 35,243 Icelandic controls. FINDINGS: Data for full analyses were available for 366 children with ADHD and 1047 controls. 57 large, rare CNVs were identified in children with ADHD and 78 in controls, showing a significantly increased rate of CNVs in ADHD (0·156 vs 0·075; p=8·9×10(-5)). This increased rate of CNVs was particularly high in those with intellectual disability (0·424; p=2·0×10(-6)), although there was also a significant excess in cases with no such disability (0·125, p=0·0077). An excess of chromosome 16p13.11 duplications was noted in the ADHD group (p=0·0008 after correction for multiple testing), a finding that was replicated in the Icelandic sample (p=0·031). CNVs identified in our ADHD cohort were significantly enriched for loci previously reported in both autism (p=0·0095) and schizophrenia (p=0·010). INTERPRETATION: Our findings provide genetic evidence of an increased rate of large CNVs in individuals with ADHD and suggest that ADHD is not purely a social construct. FUNDING: Action Research; Baily Thomas Charitable Trust; Wellcome Trust; UK Medical Research Council; European Union.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/genética , Aberrações Cromossômicas , Variações do Número de Cópias de DNA/genética , Estudo de Associação Genômica Ampla , Adolescente , Transtorno Autístico/genética , Criança , Pré-Escolar , Deleção Cromossômica , Feminino , Variação Genética , Humanos , Masculino , Polimorfismo de Nucleotídeo Único/genética , Esquizofrenia/genética
15.
Curr Top Behav Neurosci ; 4: 587-610, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21312414

RESUMO

Schizophrenia is a severe, debilitating and common psychiatric disorder, which directly affects approximately 1% of the population worldwide. Although previous studies have unequivocally shown that schizophrenia has a strong genetic component, our understanding of its pathophysiology remains limited. The precise genetic architecture of schizophrenia remains elusive and is likely to be complex. It is believed that multiple genetic variants, with each contributing a modest effect on disease risk, interact with environmental factors resulting in the phenotype. In this chapter, we summarise the main molecular genetic approaches that have been utilised in identifying susceptibility genes for schizophrenia and discuss the advantages and disadvantages of each approach. First, we detail the findings of linkage mapping in pedigrees (affected families), which analyse the co-segregation of polymorphic genetic markers with disease phenotype. Second, the contribution of targeted and genome-wide association studies, which compare differential allelic frequencies in schizophrenia cases and matched controls, is presented. Third, we discuss about the identification of susceptibility genes through analysis of chromosomal structural variation (gains and losses of genetic material). Lastly, we introduce the concept of re-sequencing, where the entire genome/exome is sequenced both in affected and unaffected individuals. This approach has the potential to provide a clarified picture of the majority of the genetic variation underlying disease pathogenesis.


Assuntos
Predisposição Genética para Doença , Esquizofrenia/etiologia , Esquizofrenia/genética , Animais , Mapeamento Cromossômico/métodos , Estudo de Associação Genômica Ampla/métodos , Humanos , Medição de Risco/métodos
16.
Genes Chromosomes Cancer ; 48(10): 897-907, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19603524

RESUMO

Neurofibromatosis Type I (NF1) is an autosomal dominant disorder characterized by the development of both benign and malignant tumors. The lifetime risk for developing a malignant peripheral nerve sheath tumor (MPNST) in NF1 patients is approximately 10% with poor survival rates. To date, the molecular basis of MPNST development remains unclear. Here, we report the first genome-wide and high-resolution analysis of DNA copy number alterations in MPNST using the 32K bacterial artificial chromosome microarray on a series of 24 MPNSTs and three neurofibroma samples. In the benign neurofibromas, apart from loss of one copy of the NF1 gene and copy number polymorphisms, no other changes were found. The profiles of malignant samples, however, revealed specific loss of chromosomal regions including 1p35-33, 1p21, 9p21.3, 10q25, 11q22-23, 17q11, and 20p12.2 as well as gain of 1q25, 3p26, 3q13, 5p12, 5q11.2-q14, 5q21-23, 5q31-33, 6p23-p21, 6p12, 6q15, 6q23-q24, 7p22, 7p14-p13, 7q21, 7q36, 8q22-q24, 14q22, and 17q21-q25. Copy number gains were more frequent than deletions in the MPNST samples (62% vs. 38%). The genes resident within common regions of gain were NEDL1 (7p14), AP3B1 (5q14.1), and CUL1 (7q36.1) and these were identified in >63% MPNSTs. The most frequently deleted locus encompassed CDKN2A, CDKN2B, and MTAP genes on 9p21.3 (33% cases). These genes have previously been implicated in other cancer conditions and therefore, should be considered for their therapeutic, prognostic, and diagnostic relevance in NF1 tumorigenesis.


Assuntos
Hibridização Genômica Comparativa/métodos , Genes da Neurofibromatose 1 , Neoplasias da Bainha Neural/genética , Neurofibromatose 1/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Neoplasias Cutâneas/genética , Adulto , Aberrações Cromossômicas , Cromossomos Artificiais Bacterianos , Feminino , Dosagem de Genes , Genoma Humano , Humanos , Masculino , Pessoa de Meia-Idade
17.
Hum Mol Genet ; 18(8): 1497-503, 2009 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-19181681

RESUMO

We investigated the involvement of rare (<1%) copy number variants (CNVs) in 471 cases of schizophrenia and 2792 controls that had been genotyped using the Affymetrix GeneChip 500K Mapping Array. Large CNVs >1 Mb were 2.26 times more common in cases (P = 0.00027), with the effect coming mostly from deletions (odds ratio, OR = 4.53, P = 0.00013) although duplications were also more common (OR = 1.71, P = 0.04). Two large deletions were found in two cases each, but in no controls: a deletion at 22q11.2 known to be a susceptibility factor for schizophrenia and a deletion on 17p12, at 14.0-15.4 Mb. The latter is known to cause hereditary neuropathy with liability to pressure palsies. The same deletion was found in 6 of 4618 (0.13%) cases and 6 of 36 092 (0.017%) controls in the re-analysed data of two recent large CNV studies of schizophrenia (OR = 7.82, P = 0.001), with the combined significance level for all three studies achieving P = 5 x 10(-5). One large duplication on 16p13.1, which has been previously implicated as a susceptibility factor for autism, was found in three cases and six controls (0.6% versus 0.2%, OR = 2.98, P = 0.13). We also provide the first support for a recently reported association between deletions at 15q11.2 and schizophrenia (P = 0.026). This study confirms the involvement of rare CNVs in the pathogenesis of schizophrenia and contributes to the growing list of specific CNVs that are implicated.


Assuntos
Dosagem de Genes , Esquizofrenia/genética , Feminino , Deleção de Genes , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Reino Unido
18.
Clin Cancer Res ; 14(4): 1015-24, 2008 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18281533

RESUMO

PURPOSE: Neurofibromatosis type 1 (NF1) is an autosomal dominant condition that predisposes to benign and malignant tumors. The lifetime risk of a malignant peripheral nerve sheath tumor (MPNST) in NF1 is approximately 10%. These tumors have a poor survival rate and their molecular basis remains unclear. We report the first comprehensive investigation of DNA copy number across multitude of genes in NF1 tumors using high-resolution array comparative genomic hybridization (CGH), with the aim to identify molecular signatures that delineate malignant from benign NF1 tumors. EXPERIMENTAL DESIGN: We constructed an exon-level resolution microarray encompassing 57 selected genes and profiled DNA from 35 MPNSTs, 16 plexiform, and 8 dermal neurofibromas. Bioinformatic analysis was done on array CGH data to identify concurrent aberrations in malignant tumors. RESULTS: The array CGH profiles of MPNSTs and neurofibromas were markedly different. A number of MPNST-specific alterations were identified, including amplifications of ITGB4, PDGFRA, MET, TP73, and HGF plus deletions in NF1, HMMR/RHAMM, MMP13, L1CAM2, p16INK4A/CDKN2A, and TP53. Copy number changes of HMMR/RHAMM, MMP13, p16INK4A/CDKN2A, and ITGB4 were observed in 46%, 43%, 39%, and 32%, respectively of the malignant tumors, implicating these genes in MPNST pathogenesis. Concomitant amplifications of HGF, MET, and PDGFRA genes were also revealed in MPNSTs, suggesting the putative role of p70S6K pathway in NF1 tumor progression. CONCLUSIONS: This study highlights the potential of array CGH in identifying novel diagnostic markers for MPNSTs.


Assuntos
Biomarcadores Tumorais/genética , Dosagem de Genes , Perfilação da Expressão Gênica , Neoplasias da Bainha Neural/genética , Humanos , Processamento de Imagem Assistida por Computador , Neurofibroma/genética , Neurofibromatose 1/complicações , Neurofibromatose 1/genética , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA
19.
Genes Chromosomes Cancer ; 47(3): 238-46, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18069666

RESUMO

Telomerase activity (TA) and the expression of its enzymatic subunits, which have been demonstrated in many tumors, remain poorly investigated in tumors associated with neurofibromatosis type 1 (NF1). In this study, we analysed the association of TA and the expression of telomerase RNA (TR) and telomerase reverse transcriptase (TERT) in 23 malignant peripheral nerve sheath tumors (MPNST) (17 high grade and 6 low grade tumors), 11 plexiform neurofibromas (PNF) and 6 dermal neurofibromas (DNF). TA was studied using telomerase repeat amplification protocol (TRAP) assay and expression of TR and TERT was investigated using reverse transcription PCR (RT-PCR) and real-time PCR. TA was detected in 14 out of 17 (82%) high grade MPNST, whereas all 6 low grade MPNST and 17 benign tumors were telomerase negative. The TERT transcripts were detected in all high grade MPNST, 50% of the low grade MPNST, and 4 benign tumors. However, the expression level of the TERT strikingly correlated with TA and high grade MPNST. Thus, while TERT expression was similar in both low grade MPNST and PNF (P = 0.115), it was significantly higher in high grade MPNST when compared to either low grade MPNST (P = 0.042), PNF (P = 0.001) or DNF tumors (P = 0.010). These findings indicate that TA and expression level of TERT are potential markers for high grade malignancy in NF1 patients.


Assuntos
Neoplasias da Bainha Neural/diagnóstico , Neurofibromatose 1/complicações , RNA/análise , Índice de Gravidade de Doença , Telomerase/análise , Telomerase/metabolismo , Biomarcadores/análise , Humanos , Neoplasias da Bainha Neural/etiologia , Neurofibroma/diagnóstico , Neurofibroma Plexiforme/diagnóstico
20.
BMC Genomics ; 8: 16, 2007 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-17222329

RESUMO

BACKGROUND: Meningiomas are the most common intracranial neoplasias, representing a clinically and histopathologically heterogeneous group of tumors. The neurofibromatosis type 2 (NF2) tumor suppressor is the only gene known to be frequently involved in early development of meningiomas. The objective of this study was to identify genetic and/or epigenetic factors contributing to the development of these tumors. A large set of sporadic meningiomas were analyzed for presence of 22q macro-mutations using array-CGH in order to identify tumors carrying gene dosage aberrations not encompassing NF2. The NF2 locus was also comprehensively studied for point mutations within coding and conserved non-coding sequences. Furthermore, CpG methylation within the NF2 promoter region was thoroughly analyzed. RESULTS: Monosomy 22 was the predominant finding, detected in 47% of meningiomas. Thirteen percent of the tumors contained interstitial/terminal deletions and gains, present singly or in combinations. We defined at least two minimal overlapping regions outside the NF2 locus that are small enough (approximately 550 kb and approximately 250 kb) to allow analysis of a limited number of candidate genes. Bialleinactivationo the NF2 gne was detected in 36% of meningiomas. Among the monosomy 22 cases, no additional NF2 mutations could be identified in 35% (17 out of 49) of tumors. Furthermore, the majority of tumors (9 out of 12) with interstitial/terminal deletions did not have any detectable NF2 mutations. Methylation within the NF2 promoter region was only identified at a single CpG site in one tumor sample. CONCLUSION: We confirmed previous findings of pronounced differences in mutation frequency between different histopathological subtypes. There is a higher frequency of biallelic NF2 inactivation in fibroblastic (52%) compared to meningothelial (18%) tumors. The presence of macro-mutations on 22q also shows marked differences between fibroblastic (86%) and meningothelial (39%) subtypes. Thus, inactivation of NF2, often combined with the presence of macro-mutation on 22q, is likely not as important for the development of the meningothelial subtype, as opposed to the fibroblastic form. Analysis of 40 CpG sites distributed within 750 bp of the promoter region suggests that NF2 promoter methylation does not play a major role in meningioma development.


Assuntos
Cromossomos Humanos Par 22 , Epigênese Genética , Genes da Neurofibromatose 2 , Neoplasias Meníngeas/genética , Meningioma/genética , Mutação , Cromossomos Humanos Par 1 , Metilação de DNA , Éxons , Humanos , Neoplasias Meníngeas/patologia , Meningioma/patologia , Monossomia , Hibridização de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA