RESUMO
We previously showed that mutations in LIS1 and DCX account for approximately 85% of patients with the classic form of lissencephaly (LIS). Some rare forms of LIS are associated with a disproportionately small cerebellum, referred to as lissencephaly with cerebellar hypoplasia (LCH). Tubulin alpha1A (TUBA1A), encoding a critical structural subunit of microtubules, has recently been implicated in LIS. Here, we screen the largest cohort of unexplained LIS patients examined to date to determine: (i) the frequency of TUBA1A mutations in patients with lissencephaly, (ii) the spectrum of phenotypes associated with TUBA1A mutations and (iii) the functional consequences of different TUBA1A mutations on microtubule function. We identified novel and recurrent TUBA1A mutations in approximately 1% of children with classic LIS and in approximately 30% of children with LCH, making this the first major gene associated with the rare LCH phenotype. We also unexpectedly found a TUBA1A mutation in one child with agenesis of the corpus callosum and cerebellar hypoplasia without LIS. Thus, our data demonstrate a wider spectrum of phenotypes than previously reported and allow us to propose new recommendations for clinical testing. We also provide cellular and structural data suggesting that LIS-associated mutations of TUBA1A operate via diverse mechanisms that include disruption of binding sites for microtubule-associated proteins (MAPs).
Assuntos
Movimento Celular , Lisencefalia/genética , Mutação , Neurônios/fisiologia , Tubulina (Proteína)/metabolismo , Encéfalo/patologia , Movimento Celular/genética , Células Cultivadas , Criança , Feminino , Estudos de Associação Genética , Humanos , Lisencefalia/patologia , Masculino , Modelos Moleculares , Mutação/fisiologia , Neurônios/metabolismo , Polimorfismo de Nucleotídeo Único , Ligação Proteica/genética , Estrutura Secundária de Proteína/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Transfecção , Tubulina (Proteína)/química , Tubulina (Proteína)/genéticaRESUMO
BACKGROUND: Postpartum fungal endogenous endophthalmitis is an extremely rare condition, particularly in young healthy women. It can lead to permanent vision loss. FINDINGS: We report a case of a 26-year-old lactating mother with a history of decreased vision in her right eye after a normal vaginal delivery. She was diagnosed with endogenous endophthalmitis caused by a very rare fungus, Candida ciferrii, on vitreous biopsy, 2 months after the initial presentation. After vitrectomy, she was treated with oral antifungal therapy and, subsequently, her visual acuity improved to 20/30 with quiet eye after 6 months of follow-up. CONCLUSION: Postpartum fungal endogenous endophthalmitis can present as a diagnostic and therapeutic challenge. It warrants early diagnosis and management.
Assuntos
Nível de Saúde , Lactação , Feminino , Humanos , AdultoRESUMO
BACKGROUND: A child with autism and mild microcephaly was found to have a de novo 3.3 Mb microdeletion on chromosome 1p34.2p34.3. The hypothesis is tested that this microdeletion contains one or more genes that underlie the autism phenotype in this child and in other children with autism spectrum disorders. METHODS: To search for submicroscopic chromosomal rearrangements in the child, array comparative genomic hybridisation (aCGH) was performed using a 19 K whole genome human bacterial artificial chromosome (BAC) array and the Illumina 610-Quad BeadChip microarray. Ingenuity pathway analysis (IPA) was used to construct functional biological networks to identify candidate autism genes. To identify putative functional variants in candidate genes, mutation screening was performed using polymerase chain reaction (PCR) based Sanger sequencing in 512 unrelated autism patients and 462 control subjects. RESULTS: A de novo 3.3 Mb deletion containing approximately 43 genes in chromosome 1p34.2p34.3 was identified and subsequently confirmed using fluorescence in situ hybridization (FISH). Literature review and bioinformatics analyses identified Regulating Synaptic Membrane Exocytosis 3 (RIMS3) as the most promising autism candidate gene. Mutation screening of this gene in autism patients identified five inherited coding variants, including one (p.E177A) that segregated with the autism phenotype in a sibship, was predicted to be deleterious, and was absent in 1161 controls. CONCLUSIONS: This case report and mutation screening data suggest that RIMS3 is an autism causative or contributory gene. Functional studies of RIMS3 variants such as p.E177A should provide additional insight into the role of synaptic proteins in the pathophysiology of autism.
Assuntos
Transtorno Autístico/genética , Proteínas de Membrana Transportadoras/genética , Proteínas do Tecido Nervoso/genética , Deleção de Sequência , Substituição de Aminoácidos , Criança , Pré-Escolar , Hibridização Genômica Comparativa , Análise Mutacional de DNA , Bases de Dados Genéticas , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Mutação de Sentido IncorretoRESUMO
Autism is a childhood neurodevelopmental disorder with a strong genetic component, yet the identification of autism susceptibility loci remains elusive. We investigated 180 autism probands and 372 control subjects by array comparative genomic hybridization (aCGH) using a 19K whole-genome tiling path bacterial artificial chromosome microarray to identify submicroscopic chromosomal rearrangements specific to autism. We discovered a recurrent 16p11.2 microdeletion in two probands with autism and none in controls. The deletion spans approximately 500-kb and is flanked by approximately 147-kb segmental duplications (SDs) that are >99% identical, a common characteristic of genomic disorders. We assessed the frequency of this new autism genomic disorder by screening an additional 532 probands and 465 controls by quantitative PCR and identified two more patients but no controls with the microdeletion, indicating a combined frequency of 0.6% (4/712 autism versus 0/837 controls; Fisher exact test P = 0.044). We confirmed all 16p11.2 deletions using fluorescence in situ hybridization, microsatellite analyses and aCGH, and mapped the approximate deletion breakpoints to the edges of the flanking SDs using a custom-designed high-density oligonucleotide microarray. Bioinformatic analysis localized 12 of the 25 genes within the microdeletion to nodes in one interaction network. We performed phenotype analyses and found no striking features that distinguish patients with the 16p11.2 microdeletion as a distinct autism subtype. Our work reports the first frequency, breakpoint, bioinformatic and phenotypic analyses of a de novo 16p11.2 microdeletion that represents one of the most common recurrent genomic disorders associated with autism to date.
Assuntos
Transtorno Autístico/genética , Deleção Cromossômica , Cromossomos Humanos Par 16/genética , Sequência de Bases , Estudos de Casos e Controles , Criança , Quebra Cromossômica , Cromossomos Artificiais Bacterianos/genética , Primers do DNA/genética , Feminino , Frequência do Gene , Predisposição Genética para Doença , Humanos , Hibridização in Situ Fluorescente , Masculino , Repetições de Microssatélites , Linhagem , Fenótipo , Reação em Cadeia da PolimeraseRESUMO
Submicroscopic recurrent 16p11.2 rearrangements are associated with several neurodevelopmental disorders, including autism, mental retardation, and schizophrenia. The common 16p11.2 region includes 24 known genes, of which 22 are expressed in the developing human fetal nervous system. As yet, the mechanisms leading to neurodevelopmental abnormalities and the broader phenotypes associated with deletion or duplication of 16p11.2 have not been clarified. Here we report a child with spastic quadriparesis, refractory infantile seizures, severe global developmental delay, hypotonia, and microcephaly, and a de novo 598 kb 16p11.2 microduplication. Family history is negative for any of these features in parents and immediate family members. Sequencing analyses showed no mutations in DOC2A, QPRT, and SEZ6L2, genes within the duplicated 16p11.2 region that have been implicated in neuronal function and/or seizure related phenotypes. The child's clinical course is consistent with a rare seizure disorder called malignant migrating partial seizure disorder of infancy, raising the possibility that duplication or disruption of genes in the 16p11.2 interval may contribute to this severe disorder.
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 16/genética , Convulsões/genética , Humanos , Lactente , Masculino , SíndromeRESUMO
Autism spectrum disorders (ASDs) are a clinically complex group of childhood disorders that have firm evidence of an underlying genetic etiology. Many techniques have been used to characterize the genetic bases of ASDs. Linkage studies have identified several replicated susceptibility loci, including 2q24-2q31, 7q, and 17q11-17q21. Association studies and mutation analysis of candidate genes have implicated the synaptic genes NRXN1, NLGN3, NLGN4, SHANK3, and CNTNAP2 in ASDs. Traditional cytogenetic approaches highlight the high frequency of large chromosomal abnormalities (3%-7% of patients), including the most frequently observed maternal 15q11-13 duplications (1%-3% of patients). Newly developed techniques include high-resolution DNA microarray technologies, which have discovered formerly undetectable submicroscopic copy number variants, and genomewide association studies, which allow simultaneous detection of multiple genes associated with ASDs. Although great progress has been made in autism genetics, the molecular bases of most ASDs remains enigmatic.
Assuntos
Transtorno Autístico/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Mapeamento Cromossômico , Análise Mutacional de DNA , HumanosRESUMO
Nuclear receptor 2E1 gene (NR2E1) resides within a 6q21-22 locus for bipolar disorder and schizophrenia. Mice deleted for Nr2e1 show altered neurogenesis, cortical and limbic abnormalities, aggression, hyperexcitability, and cognitive impairment. NR2E1 is therefore a positional and functional candidate for involvement in mental illness. We performed association analyses in 394 patients with bipolar disorder, 396 with schizophrenia, and 479 controls using six common markers and haplotypes. We also performed a comprehensive mutation screen of NR2E1, resequencing its entire coding region, complete 5' and 3' untranslated regions, consensus splice-sites, and evolutionarily conserved regions in 126 humans with bipolar disorder, schizophrenia, or aggressive disorders. NR2E1 was associated with bipolar disorder I and II [odds ratio (OR = 0.77, P = 0.013), bipolar disorder I (OR = 0.77, P = 0.015), bipolar disorder in females (OR = 0.72, P = 0.009), and with age at onset < or = 25 years (OR = 0.67, P = 0.006)], all of which remained significant after correcting for multiple comparisons. We identified eight novel candidate mutations that were absent in 325 controls; four of these were predicted to alter known neural transcription factor binding sites. Analyses of NR2E1 mRNA in human brain revealed forebrain-specific transcription. The data presented support the hypothesis that genetic variation at NR2E1 may be associated with susceptibility to brain-behavior disorders.
Assuntos
Agressão/fisiologia , Transtorno Bipolar/genética , Análise Mutacional de DNA/métodos , Ligação Genética , Receptores Citoplasmáticos e Nucleares/genética , Esquizofrenia/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Frequência do Gene , Predisposição Genética para Doença , Humanos , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Mutação/fisiologia , Receptores Nucleares Órfãos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND: A disruption of sorting nexin 3 (SNX3) on 6q21 was previously reported in a patient with MMEP (microcephaly, microphthalmia, ectrodactyly, and prognathism) and t(6;13)(q21;q12) but no SNX3 mutations were identified in another sporadic case of MMEP, suggesting involvement of another gene. In this work, SNX3 was sequenced in three patients not previously studied for this gene. In addition, we test the hypothesis that mutations in the neighbouring gene NR2E1 may underlie MMEP and related phenotypes. METHODS: Mutation screening was performed in five patients: the t(6;13)(q21;q12) MMEP patient, three additional patients with possible MMEP or a related phenotype, and one patient with oligodactyly, ulnar aplasia, and a t(6;7)(q21;q31.2) translocation. We used sequencing to exclude SNX3 coding mutations in three patients not previously studied for this gene. To test the hypothesis that mutations in NR2E1 may contribute to MMEP or related phenotypes, we sequenced the entire coding region, complete 5' and 3' untranslated regions, consensus splice-sites, and evolutionarily conserved regions including core and proximal promoter in all five patients. Two-hundred and fifty control subjects were genotyped for any candidate mutation. RESULTS: We did not detect any synonymous nor nonsynonymous coding mutations of NR2E1 or SNX3. In one patient with possible MMEP, we identified a candidate regulatory mutation that has been reported previously in a patient with microcephaly but was not found in 250 control subjects examined here. CONCLUSION: Our results do not support involvement of coding mutations in NR2E1 or SNX3 in MMEP or related phenotypes; however, we cannot exclude the possibility that regulatory NR2E1 or SNX3 mutations or deletions at this locus may underlie abnormal human cortical development in some patients.
Assuntos
Anormalidades Múltiplas/genética , Mutação , Receptores Citoplasmáticos e Nucleares/genética , Proteínas de Transporte Vesicular/genética , Adulto , Criança , Cromossomos Humanos Par 6 , Códon , Ectromelia/genética , Feminino , Humanos , Masculino , Microcefalia/genética , Microftalmia/genética , Receptores Nucleares Órfãos , Fenótipo , Prognatismo/genética , Sequências Reguladoras de Ácido Nucleico , Análise de Sequência de DNA , Nexinas de Classificação , SíndromeRESUMO
The past two decades have yielded a recognition that intimate partner violence is ubiquitous. Although violence within relationships is bidirectional, there is acknowledgment that violence directed against women is more persistent and dangerous. Strategies for treatment of men have been largely unsuccessful, and studies of women centered approaches to prevention are in their infancy. An emerging concept in the brain-behavior field is the recognition of genetics as a powerful influence on aggressive and violent behaviors. Mouse models of human health and disease have facilitated our understanding of the role of genetics in the manifestation of these traits. There is a need to push the boundaries of research on intimate partner violence by adopting biosocial approaches to understand its causes.
Assuntos
Agressão , Pesquisa em Genética , Genética Comportamental , Delitos Sexuais , Maus-Tratos Conjugais , Animais , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Monoaminoxidase/genética , Medição de Risco , Fatores de Risco , Delitos Sexuais/prevenção & controle , Maus-Tratos Conjugais/prevenção & controleRESUMO
Copy number variants (CNVs) of a 600 kb region on 16p11.2 are associated with neurodevelopmental disorders and changes in brain volume. The authors hypothesize that abnormal brain development associated with this CNV can be attributed to changes in transcriptional regulation. The authors determined the effects of 16p11.2 dosage on gene expression by transcription profiling of lymphoblast cell lines derived from 6 microdeletion carriers, 15 microduplication carriers and 15 controls. Gene dosage had a significant influence on the transcript abundance of a majority (20/34) of genes within the CNV region. In addition, a limited number of genes were dysregulated in trans. Genes most strongly correlated with patient head circumference included SULT1A, KCTD13, and TMEM242. Given the modest effect of 16p11.2 copy number on global transcriptional regulation in lymphocytes, larger studies utilizing neuronal cell types may be needed in order to elucidate the signaling pathways that influence brain development in this genetic disorder.
Assuntos
Cromossomos Humanos Par 16 , Variações do Número de Cópias de DNA , Duplicação Gênica , Deleção de Sequência , Transcriptoma/genética , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/metabolismo , Transtorno do Espectro Autista/patologia , Linhagem Celular , Expressão Gênica/genética , Cabeça/patologia , Herpesvirus Humano 4 , Humanos , Linfonodos/citologia , Linfonodos/metabolismo , Análise em Microsséries , Tamanho do Órgão , Reação em Cadeia da Polimerase em Tempo Real , Esquizofrenia/genética , Esquizofrenia/metabolismo , Esquizofrenia/patologiaRESUMO
Infantile spasms (ISS) are an epilepsy disorder frequently associated with severe developmental outcome and have diverse genetic etiologies. We ascertained 11 subjects with ISS and novel copy number variants (CNVs) and combined these with a new cohort with deletion 1p36 and ISS, and additional published patients with ISS and other chromosomal abnormalities. Using bioinformatics tools, we analyzed the gene content of these CNVs for enrichment in pathways of pathogenesis. Several important findings emerged. First, the gene content was enriched for the gene regulatory network involved in ventral forebrain development. Second, genes in pathways of synaptic function were overrepresented, significantly those involved in synaptic vesicle transport. Evidence also suggested roles for GABAergic synapses and the postsynaptic density. Third, we confirm the association of ISS with duplication of 14q12 and maternally inherited duplication of 15q11q13, and report the association with duplication of 21q21. We also present a patient with ISS and deletion 7q11.3 not involving MAGI2. Finally, we provide evidence that ISS in deletion 1p36 may be associated with deletion of KLHL17 and expand the epilepsy phenotype in that syndrome to include early infantile epileptic encephalopathy. Several of the identified pathways share functional links, and abnormalities of forebrain synaptic growth and function may form a common biologic mechanism underlying both ISS and autism. This study demonstrates a novel approach to the study of gene content in subjects with ISS and copy number variation, and contributes further evidence to support specific pathways of pathogenesis.
Assuntos
Dosagem de Genes , Prosencéfalo/metabolismo , Espasmos Infantis/genética , Aberrações Cromossômicas , Biologia Computacional , Redes Reguladoras de Genes , Loci Gênicos , Humanos , Lactente , Recém-Nascido , Prosencéfalo/anormalidades , Transmissão Sináptica/genéticaRESUMO
We recently reported an autistic proband and affected sibling with maternally inherited microduplications within the 15q13.1 and 15q13.3 regions that contain a total of 4 genes. The amyloid precursor protein-binding protein A2 (APBA2) gene is located within the 15q13.1 duplication and encodes a neuronal adaptor protein essential to synaptic transmission that interacts directly with NRXN1 at the presynaptic membrane. We interpreted this as evidence for a putative role of APBA2 in autism as larger maternal duplications of 15q11-q13 are the most common known cause of autism. We therefore resequenced 512 subjects with autism spectrum disorder (ASD) and 463 controls, and identified 7 novel nonsynonymous coding variants in ASD subjects compared with 4 in controls. Five of the seven variants in the ASD group were predicted to affect protein function, alter residues conserved across 18 species, or both. All of the variants for which parental DNA was available were inherited. We also found two different nonsynonymous variants in two siblings with autism: (1) a paternally inherited heterozygous 6 bp deletion and (2) a maternally inherited heterozygous missense mutation, the latter also found in a single control. These results indicate compound heterozygous mutations of APBA2 in this autism sibship. The co-occurrence of two nonsynonymous mutations in both affected siblings in a single family, each transmitted from a different unaffected parent, suggest a role for APBA2 mutations in rare individuals with ASD.
Assuntos
Caderinas/genética , Proteínas de Transporte/genética , Transtornos Globais do Desenvolvimento Infantil/genética , Variações do Número de Cópias de DNA/genética , Estudos de Associação Genética , Variação Genética/genética , Proteínas do Tecido Nervoso/genética , Alelos , Proteínas de Ligação ao Cálcio , Moléculas de Adesão Celular Neuronais , Criança , Transtornos Globais do Desenvolvimento Infantil/diagnóstico , Transtornos Globais do Desenvolvimento Infantil/psicologia , Deleção Cromossômica , Cromossomos Humanos Par 15/genética , Análise Mutacional de DNA , Epistasia Genética/genética , Éxons/genética , Feminino , Duplicação Gênica , Frequência do Gene/genética , Triagem de Portadores Genéticos , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Mutação de Sentido Incorreto , Moléculas de Adesão de Célula Nervosa , Fases de Leitura Aberta/genética , Linhagem , Fenótipo , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNA , Transmissão Sináptica/genéticaRESUMO
The XVI World Congress of Psychiatric Genetics, sponsored by the International Society of Psychiatric Genetics took place in Osaka, Japan, October 2008. Approximately 600 participants gathered to discuss the latest molecular genetic findings relevant to serious mental illnesses, including schizophrenia, bipolar disorder, major depression, alcohol and drug abuse, autism, and attention-deficit disorder. Recently, the field has advanced considerably and includes new genome-wide association studies with the largest numbers of individuals screened and density of markers to date, as well as newly uncovered genetic phenomena, such as copy number variation that may prove to be relevant for specific brain disorders. The following report represents some of the areas covered during this conference and some of the major new findings presented.
Assuntos
Transtornos Mentais/genética , Animais , Ansiedade/genética , Transtorno do Deficit de Atenção com Hiperatividade/genética , Encéfalo/embriologia , Encéfalo/metabolismo , Ritmo Circadiano/genética , Descoberta de Drogas , Dosagem de Genes , Estudo de Associação Genômica Ampla , Geriatria , Humanos , Japão , Camundongos , MicroRNAs/metabolismo , Farmacogenética , Fenótipo , Esquizofrenia/genética , Sono/genética , Transtornos Relacionados ao Uso de Substâncias/genéticaRESUMO
BACKGROUND: Autism is a complex childhood neurodevelopmental disorder with a strong genetic basis. Microdeletion or duplication of a approximately 500-700-kb genomic rearrangement on 16p11.2 that contains 24 genes represents the second most frequent chromosomal disorder associated with autism. The role of common and rare 16p11.2 sequence variants in autism etiology is unknown. METHODOLOGY/PRINCIPAL FINDINGS: To identify common 16p11.2 variants with a potential role in autism, we performed association studies using existing data generated from three microarray platforms: Affymetrix 5.0 (777 families), Illumina 550 K (943 families), and Affymetrix 500 K (60 families). No common variants were identified that were significantly associated with autism. To look for rare variants, we performed resequencing of coding and promoter regions for eight candidate genes selected based on their known expression patterns and functions. In total, we identified 26 novel variants in autism: 13 exonic (nine non-synonymous, three synonymous, and one untranslated region) and 13 promoter variants. We found a significant association between autism and a coding variant in the seizure-related gene SEZ6L2 (12/1106 autism vs. 3/1161 controls; p = 0.018). Sez6l2 expression in mouse embryos was restricted to the spinal cord and brain. SEZ6L2 expression in human fetal brain was highest in post-mitotic cortical layers, hippocampus, amygdala, and thalamus. Association analysis of SEZ6L2 in an independent sample set failed to replicate our initial findings. CONCLUSIONS/SIGNIFICANCE: We have identified sequence variation in at least one candidate gene in 16p11.2 that may represent a novel genetic risk factor for autism. However, further studies are required to substantiate these preliminary findings.
Assuntos
Transtorno Autístico/genética , Cromossomos Humanos Par 16/genética , Variação Genética , Proteínas de Membrana/genética , Animais , Transtorno Autístico/etiologia , Análise Mutacional de DNA , Embrião de Mamíferos , Éxons/genética , Saúde da Família , Predisposição Genética para Doença , Humanos , Camundongos , Regiões Promotoras Genéticas/genéticaRESUMO
Recurrent microdeletions and microduplications of a 600-kb genomic region of chromosome 16p11.2 have been implicated in childhood-onset developmental disorders. We report the association of 16p11.2 microduplications with schizophrenia in two large cohorts. The microduplication was detected in 12/1,906 (0.63%) cases and 1/3,971 (0.03%) controls (P = 1.2 x 10(-5), OR = 25.8) from the initial cohort, and in 9/2,645 (0.34%) cases and 1/2,420 (0.04%) controls (P = 0.022, OR = 8.3) of the replication cohort. The 16p11.2 microduplication was associated with a 14.5-fold increased risk of schizophrenia (95% CI (3.3, 62)) in the combined sample. A meta-analysis of datasets for multiple psychiatric disorders showed a significant association of the microduplication with schizophrenia (P = 4.8 x 10(-7)), bipolar disorder (P = 0.017) and autism (P = 1.9 x 10(-7)). In contrast, the reciprocal microdeletion was associated only with autism and developmental disorders (P = 2.3 x 10(-13)). Head circumference was larger in patients with the microdeletion than in patients with the microduplication (P = 0.0007).
Assuntos
Cromossomos Humanos Par 16 , Duplicação Gênica , Predisposição Genética para Doença , Esquizofrenia/genética , Humanos , Fatores de RiscoRESUMO
BACKGROUND: One genetic mechanism known to be associated with autism spectrum disorders (ASD) is chromosomal abnormalities. The identification of copy number variants (CNV), i.e., microdeletions and microduplications that are undetectable at the level of traditional cytogenetic analysis, allows the potential association of submicroscopic chromosomal imbalances and human disease. METHODS: We performed array comparative genomic hybridization (aCGH) utilizing a 19K whole genome tiling path bacterial artificial chromosome (BAC) microarray on 397 unrelated subjects with autism spectrum disorder. Common CNV were excluded using a control group comprised of 372 individuals from the National Institute of Mental Health (NIMH) Genetics Initiative Control samples. Confirmation studies were performed on all remaining CNV using fluorescence in situ hybridization (FISH), microsatellite analysis, and/or quantitative polymerase chain reaction (PCR) analysis. RESULTS: A total of 51 CNV were confirmed in 46 ASD subjects. Three maternal interstitial duplications of 15q11-q13 known to be associated with ASD were identified. The other 48 CNV ranged in size from 189 kilobase (kb) to 5.5 megabase (Mb) and contained from 0 to approximately 40 National Center for Biotechnology Information (NCBI) Reference Sequence (RefSeq) genes. Seven CNV were de novo and 44 were inherited. CONCLUSIONS: Fifty-one autism-specific CNV were identified in 46 of 397 ASD patients using a 19K BAC microarray for an overall rate of 11.6%. These microdeletions and microduplications cause gene dosage imbalance in 272 genes, many of which could be considered as candidate genes for autism.
Assuntos
Transtorno Autístico/genética , Aberrações Cromossômicas , Dosagem de Genes/genética , Variação Genética/genética , Alelos , Transtorno Autístico/diagnóstico , População Negra/genética , Criança , Deleção Cromossômica , Cromossomos Artificiais Bacterianos/genética , Cromossomos Humanos Par 15/genética , Análise Mutacional de DNA , Feminino , Duplicação Gênica , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Hibridização de Ácido Nucleico/genética , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Reação em Cadeia da Polimerase , População Branca/genéticaRESUMO
The exceptional value of gene targeting technology to generate mouse models of human disease exists under the shadow of potential genetic errors. We previously observed an unexpected brain-behavior phenotype that resulted from a gene-targeting experiment designed to delete the Zfa gene. Given that the transcription of Zfa is restricted to the germ cell lineage of adult testis, it was both a surprise and a concern when the resulting mice had a phenotype present in both sexes that included abnormal brains and violent behavior. We hypothesized that an unrelated mutation may have been responsible for the unexpected phenotype. Here we show that the single gene mutation, Nr2e1(frc) (fierce), which was responsible for the brain-behavior phenotype, existed in the embryonic stem (ES) cell even before the derivation of the Zfa knockout mice. Our work thus highlights a concern in gene targeting, namely, that ES cells can harbor unexpected mutations, which can lead to genotype-phenotype misattribution. Based on our findings, we caution the gene-targeting community to use low-passage ES cells, to characterize mice derived from more than one independently targeted ES cell clone, and to backcross mice to allow for segregation of distant but linked mutations.