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Patel C, Cooper-Charles L, McMullan DJ, Walker JM, Davison V, Morton J. Translocation breakpoint at 7q31 associated with tics: further evidence for IMMP2L as a candidate gene for Tourette syndrome. Eur J Hum Genet 2011; 19:634-9. [PMID: 21386874 DOI: 10.1038/ejhg.2010.238] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Gilles de la Tourette syndrome is a complex neuropsychiatric disorder with a strong genetic basis. We identified a male patient with Tourette syndrome-like tics and an apparently balanced de novo translocation [46,XY,t(2;7)(p24.2;q31)]. Further analysis using array comparative genomic hybridisation (CGH) revealed a cryptic deletion at 7q31.1-7q31.2. Breakpoints disrupting this region have been reported in one isolated and one familial case of Tourette syndrome. In our case, IMMP2L, a gene coding for a human homologue of the yeast inner mitochondrial membrane peptidase subunit 2, was disrupted by the breakpoint on 7q31.1, with deletion of exons 1-3 of the gene. The IMMP2L gene has previously been proposed as a candidate gene for Tourette syndrome, and our case provides further evidence of its possible role in the pathogenesis. The deleted region (7q31.1-7q31.2) of 7.2 Mb of genomic DNA also encompasses numerous genes, including FOXP2, associated with verbal dyspraxia, and the CFTR gene.
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Affiliation(s)
- Chirag Patel
- Department of Clinical Genetics, Birmingham Women's Hospital NHS Foundation Trust, Birmingham, UK.
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102
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State MW. The genetics of Tourette disorder. Curr Opin Genet Dev 2011; 21:302-9. [PMID: 21277193 DOI: 10.1016/j.gde.2011.01.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 01/03/2011] [Accepted: 01/04/2011] [Indexed: 12/21/2022]
Abstract
Tourette disorder (TD) is a childhood onset neuropsychiatric syndrome defined by persistent motor and vocal tics. Despite a long-standing consensus for a strong genetic contribution, the pace of discovery compared to other disorders of similar prevalence has been slow, due in part to a paucity of studies and both clinical heterogeneity and a complex genetic architecture. However, the potential for rapid progress is high. Recent rare variant findings have pointed to the importance of copy number variation, the overlap of risks among distinct diagnostic entities, the contribution of novel molecular mechanisms, and the value of family based studies. Finally, analysis of a cohort of sufficient size to identify common polymorphisms of plausible effect is underway, promising key information regarding the contribution of common alleles to TD.
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Affiliation(s)
- Matthew W State
- Department of Child Psychiatry, Yale University School of Medicine, New Haven, CT 06520, United States.
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Wang LS, Hranilovic D, Wang K, Lindquist IE, Yurcaba L, Petkovic ZB, Gidaya N, Jernej B, Hakonarson H, Bucan M. Population-based study of genetic variation in individuals with autism spectrum disorders from Croatia. BMC MEDICAL GENETICS 2010; 11:134. [PMID: 20858243 PMCID: PMC2954843 DOI: 10.1186/1471-2350-11-134] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 09/21/2010] [Indexed: 12/21/2022]
Abstract
Background Genome-wide studies on autism spectrum disorders (ASDs) have mostly focused on large-scale population samples, but examination of rare variations in isolated populations may provide additional insights into the disease pathogenesis. Methods As a first step in the genetic analysis of ASD in Croatia, we characterized genetic variation in a sample of 103 subjects with ASD and 203 control individuals, who were genotyped using the Illumina HumanHap550 BeadChip. We analyzed the genetic diversity of the Croatian population and its relationship to other populations, the degree of relatedness via Runs of Homozygosity (ROHs), and the distribution of large (>500 Kb) copy number variations. Results Combining the Croatian cohort with several previously published populations in the FastME analysis (an alternative to Neighbor Joining) revealed that Croatian subjects cluster, as expected, with Southern Europeans; in addition, individuals from the same geographic region within Europe cluster together. Whereas Croatian subjects could be separated from a sample of healthy control subjects of European origin from North America, Croatian ASD cases and controls are well mixed. A comparison of runs of homozygosity indicated that the number and the median length of regions of homozygosity are higher for ASD subjects than for controls (p = 6 × 10-3). Furthermore, analysis of copy number variants found a higher frequency of large chromosomal rearrangements (>2 Mb) in ASD cases (5/103) than in ethnically matched control subjects (1/197, p = 0.019). Conclusions Our findings illustrate the remarkable utility of high-density genotype data for subjects from a limited geographic area in dissecting genetic heterogeneity with respect to population and disease related variation.
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Affiliation(s)
- Li-San Wang
- Department of Pathology, Laboratory Medicine, Biomedical Graduate Studies, University of Pennsylvania, Philadelphia 19104, USA.
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Holt R, Barnby G, Maestrini E, Bacchelli E, Brocklebank D, Sousa I, Mulder EJ, Kantojärvi K, Järvelä I, Klauck SM, Poustka F, Bailey AJ, Monaco AP. Linkage and candidate gene studies of autism spectrum disorders in European populations. Eur J Hum Genet 2010; 18:1013-9. [PMID: 20442744 PMCID: PMC2987412 DOI: 10.1038/ejhg.2010.69] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 04/07/2010] [Accepted: 04/08/2010] [Indexed: 02/05/2023] Open
Abstract
Over the past decade, research on the genetic variants underlying susceptibility to autism and autism spectrum disorders (ASDs) has focused on linkage and candidate gene studies. This research has implicated various chromosomal loci and genes. Candidate gene studies have proven to be particularly intractable, with many studies failing to replicate previously reported associations. In this paper, we investigate previously implicated genomic regions for a role in ASD susceptibility, using four cohorts of European ancestry. Initially, a 384 SNP Illumina GoldenGate array was used to examine linkage at six previously implicated loci. We identify linkage approaching genome-wide suggestive levels on chromosome 2 (rs2885116, MLOD=1.89). Association analysis showed significant associations in MKL2 with ASD (rs756472, P=4.31 x 10(-5)) and between SND1 and strict autism (rs1881084, P=7.76 x 10(-5)) in the Finnish and Northern Dutch populations, respectively. Subsequently, we used a second 384 SNP Illumina GoldenGate array to examine the association in seven candidate genes, and evidence for association was found in RELN (rs362780, P=0.00165). Further increasing the sample size strengthened the association with RELN (rs362780, P=0.001) and produced a second significant result in GRIK2 (rs2518261, P=0.008). Our results strengthen the case for a more detailed study of the role of RELN and GRIK2 in autism susceptibility, as well as identifying two new potential candidate genes, MKL2 and SND1.
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Affiliation(s)
- Richard Holt
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Gabrielle Barnby
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Elena Maestrini
- Dipartimento di Biologia, Università di Bologna, Bologna, Italy
| | - Elena Bacchelli
- Dipartimento di Biologia, Università di Bologna, Bologna, Italy
| | - Denise Brocklebank
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Inês Sousa
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Erik J Mulder
- Department of Psychiatry, Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, The Netherlands
| | - Katri Kantojärvi
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | - Irma Järvelä
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
| | - Sabine M Klauck
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Fritz Poustka
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany
| | - Anthony J Bailey
- University Department of Psychiatry, Park Hospital for Children, Oxford, UK
| | - Anthony P Monaco
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - the EU Autism MOLGEN Consortium8
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
- Dipartimento di Biologia, Università di Bologna, Bologna, Italy
- Department of Psychiatry, Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, The Netherlands
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany
- University Department of Psychiatry, Park Hospital for Children, Oxford, UK
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105
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Pagnamenta AT, Bacchelli E, de Jonge MV, Mirza G, Scerri TS, Minopoli F, Chiocchetti A, Ludwig KU, Hoffmann P, Paracchini S, Lowy E, Harold DH, Chapman JA, Klauck SM, Poustka F, Houben RH, Staal WG, Ophoff RA, O'Donovan MC, Williams J, Nöthen MM, Schulte-Körne G, Deloukas P, Ragoussis J, Bailey AJ, Maestrini E, Monaco AP. Characterization of a family with rare deletions in CNTNAP5 and DOCK4 suggests novel risk loci for autism and dyslexia. Biol Psychiatry 2010; 68:320-8. [PMID: 20346443 PMCID: PMC2941017 DOI: 10.1016/j.biopsych.2010.02.002] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/15/2010] [Accepted: 02/01/2010] [Indexed: 11/16/2022]
Abstract
BACKGROUND Autism spectrum disorders (ASDs) are characterized by social, communication, and behavioral deficits and complex genetic etiology. A recent study of 517 ASD families implicated DOCK4 by single nucleotide polymorphism (SNP) association and a microdeletion in an affected sibling pair. METHODS The DOCK4 microdeletion on 7q31.1 was further characterized in this family using QuantiSNP analysis of 1M SNP array data and reverse transcription polymerase chain reaction. Extended family members were tested by polymerase chain reaction amplification of junction fragments. DOCK4 dosage was measured in additional samples using SNP arrays. Since QuantiSNP analysis identified a novel CNTNAP5 microdeletion in the same affected sibling pair, this gene was sequenced in 143 additional ASD families. Further polymerase chain reaction-restriction fragment length polymorphism analysis included 380 ASD cases and suitable control subjects. RESULTS The maternally inherited microdeletion encompassed chr7:110,663,978-111,257,682 and led to a DOCK4-IMMP2L fusion transcript. It was also detected in five extended family members with no ASD. However, six of nine individuals with this microdeletion had poor reading ability, which prompted us to screen 606 other dyslexia cases. This led to the identification of a second DOCK4 microdeletion co-segregating with dyslexia. Assessment of genomic background in the original ASD family detected a paternal 2q14.3 microdeletion disrupting CNTNAP5 that was also transmitted to both affected siblings. Analysis of other ASD cohorts revealed four additional rare missense changes in CNTNAP5. No exonic deletions of DOCK4 or CNTNAP5 were seen in 2091 control subjects. CONCLUSIONS This study highlights two new risk factors for ASD and dyslexia and demonstrates the importance of performing a high-resolution assessment of genomic background, even after detection of a rare and likely damaging microdeletion using a targeted approach.
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Affiliation(s)
- Alistair T. Pagnamenta
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Elena Bacchelli
- Department of Biology, University of Bologna, Bologna, Italy
| | - Maretha V. de Jonge
- Department of Child and Adolescent Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ghazala Mirza
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Thomas S. Scerri
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Andreas Chiocchetti
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Kerstin U. Ludwig
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Per Hoffmann
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Silvia Paracchini
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Ernesto Lowy
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Denise H. Harold
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff, United Kingdom
| | - Jade A. Chapman
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff, United Kingdom
| | - Sabine M. Klauck
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Fritz Poustka
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe-University, Frankfurt/Main, Germany
| | - Renske H. Houben
- Department of Child and Adolescent Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wouter G. Staal
- Department of Child and Adolescent Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Roel A. Ophoff
- Department of Medical Genetics and Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
- University of California Los Angeles Center for Neurobehavioral Genetics, Los Angeles, California
| | | | - Julie Williams
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff, United Kingdom
| | - Markus M. Nöthen
- Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Gerd Schulte-Körne
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Panos Deloukas
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Jiannis Ragoussis
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Anthony J. Bailey
- University Department of Psychiatry, Warneford Hospital, Oxford, United Kingdom
| | - Elena Maestrini
- Department of Biology, University of Bologna, Bologna, Italy
| | - Anthony P. Monaco
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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106
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Sousa I, Clark TG, Holt R, Pagnamenta AT, Mulder EJ, Minderaa RB, Bailey AJ, Battaglia A, Klauck SM, Poustka F, Monaco AP. Polymorphisms in leucine-rich repeat genes are associated with autism spectrum disorder susceptibility in populations of European ancestry. Mol Autism 2010; 1:7. [PMID: 20678249 PMCID: PMC2913944 DOI: 10.1186/2040-2392-1-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 03/25/2010] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Autism spectrum disorders (ASDs) are a group of highly heritable neurodevelopmental disorders which are characteristically comprised of impairments in social interaction, communication and restricted interests/behaviours. Several cell adhesion transmembrane leucine-rich repeat (LRR) proteins are highly expressed in the nervous system and are thought to be key regulators of its development. Here we present an association study analysing the roles of four promising candidate genes - LRRTM1 (2p), LRRTM3 (10q), LRRN1 (3p) and LRRN3 (7q) - in order to identify common genetic risk factors underlying ASDs. METHODS In order to gain a better understanding of how the genetic variation within these four gene regions may influence susceptibility to ASDs, a family-based association study was undertaken in 661 families of European ancestry selected from four different ASD cohorts. In addition, a case-control study was undertaken across the four LRR genes, using logistic regression in probands with ASD of each population against 295 ECACC controls. RESULTS Significant results were found for LRRN3 and LRRTM3 (P < 0.005), using both single locus and haplotype approaches. These results were further supported by a case-control analysis, which also highlighted additional SNPs in LRRTM3. CONCLUSIONS Overall, our findings implicate the neuronal leucine-rich genes LRRN3 and LRRTM3 in ASD susceptibility.
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Affiliation(s)
- Inês Sousa
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
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107
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Cukier HN, Skaar DA, Rayner-Evans MY, Konidari I, Whitehead PL, Jaworski JM, Cuccaro ML, Pericak-Vance MA, Gilbert JR. Identification of chromosome 7 inversion breakpoints in an autistic family narrows candidate region for autism susceptibility. Autism Res 2010; 2:258-66. [PMID: 19877165 DOI: 10.1002/aur.96] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Chromosomal breaks and rearrangements have been observed in conjunction with autism and autistic spectrum disorders. A chromosomal inversion has been previously reported in autistic siblings, spanning the region from approximately 7q22.1 to 7q31. This family is distinguished by having multiple individuals with autism and associated disabilities. The region containing the inversion has been strongly implicated in autism by multiple linkage studies, and has been particularly associated with language defects in autism as well as in other disorders with language components. Mapping of the inversion breakpoints by FISH has localized the inversion to the region spanning approximately 99-108.75 Mb of chromosome 7. The proximal breakpoint has the potential to disrupt either the coding sequence or regulatory regions of a number of cytochrome P450 genes while the distal region falls in a relative gene desert. Copy number variant analysis of the breakpoint regions detected no duplication or deletion that could clearly be associated with disease status. Association analysis in our autism data set using single nucleotide polymorphisms located near the breakpoints showed no significant association with proximal breakpoint markers, but has identified markers near the distal breakpoint ( approximately 108-110 Mb) with significant associations to autism. The chromosomal abnormality in this family strengthens the case for an autism susceptibility gene in the chromosome 7q22-31 region and targets a candidate region for further investigation.
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Affiliation(s)
- Holly N Cukier
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, USA
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108
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Day A, Dong J, Funari VA, Harry B, Strom SP, Cohn DH, Nelson SF. Disease gene characterization through large-scale co-expression analysis. PLoS One 2009; 4:e8491. [PMID: 20046828 PMCID: PMC2797297 DOI: 10.1371/journal.pone.0008491] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 12/07/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In the post genome era, a major goal of biology is the identification of specific roles for individual genes. We report a new genomic tool for gene characterization, the UCLA Gene Expression Tool (UGET). RESULTS Celsius, the largest co-normalized microarray dataset of Affymetrix based gene expression, was used to calculate the correlation between all possible gene pairs on all platforms, and generate stored indexes in a web searchable format. The size of Celsius makes UGET a powerful gene characterization tool. Using a small seed list of known cartilage-selective genes, UGET extended the list of known genes by identifying 32 new highly cartilage-selective genes. Of these, 7 of 10 tested were validated by qPCR including the novel cartilage-specific genes SDK2 and FLJ41170. In addition, we retrospectively tested UGET and other gene expression based prioritization tools to identify disease-causing genes within known linkage intervals. We first demonstrated this utility with UGET using genetically heterogeneous disorders such as Joubert syndrome, microcephaly, neuropsychiatric disorders and type 2 limb girdle muscular dystrophy (LGMD2) and then compared UGET to other gene expression based prioritization programs which use small but discrete and well annotated datasets. Finally, we observed a significantly higher gene correlation shared between genes in disease networks associated with similar complex or Mendelian disorders. DISCUSSION UGET is an invaluable resource for a geneticist that permits the rapid inclusion of expression criteria from one to hundreds of genes in genomic intervals linked to disease. By using thousands of arrays UGET annotates and prioritizes genes better than other tools especially with rare tissue disorders or complex multi-tissue biological processes. This information can be critical in prioritization of candidate genes for sequence analysis.
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Affiliation(s)
- Allen Day
- Department of Human Genetics, Molecular Biology Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jun Dong
- Department of Human Genetics, Molecular Biology Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Vincent A. Funari
- Cedars-Sinai Medical Center, Medical Genetics Institute, Los Angeles, California, United States of America
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Bret Harry
- Department of Human Genetics, Molecular Biology Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Samuel P. Strom
- Department of Human Genetics, Molecular Biology Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Dan H. Cohn
- Department of Human Genetics, Molecular Biology Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Cedars-Sinai Medical Center, Medical Genetics Institute, Los Angeles, California, United States of America
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Stanley F. Nelson
- Department of Human Genetics, Molecular Biology Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Abstract
For more than three decades, the venom of the black widow spider and its principal active components, latrotoxins, have been used to induce release of neurotransmitters and hormones and to study the mechanisms of exocytosis. Given the complex nature of alpha--latrotoxin (alpha-LTX) actions, this research has been continuously overshadowed by many enigmas, misconceptions and perpetual changes of the underlying hypotheses. Some of the toxin's mechanisms of action are still not completely understood. Despite all these difficulties, the extensive work of several generations of neurobiologists has brought about a great deal of fascinating insights into pre-synaptic processes and has led to the discovery of several novel proteins and synaptic systems. For example, alpha-LTX studies have contributed to the widespread acceptance of the vesicular theory of transmitter release. Pre-synaptic receptors for alpha-LTX--neurexins, latrophilins and protein tyrosine phosphatase sigma--and their endogenous ligands have now become centrepieces of their own areas of research, with a potential of uncovering new mechanisms of synapse formation and regulation that may have medical implications. However, any future success of alpha-LTX research will require a better understanding of this unusual natural tool and a more precise dissection of its multiple mechanisms.
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Affiliation(s)
- John-Paul Silva
- Division of Cell and Molecular Biology, Imperial College London, Exhibition Road, London, UK
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110
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Pei F, Baldassi S, Procida G, Igliozzi R, Tancredi R, Muratori F, Cioni G. Neural correlates of texture and contour integration in children with autism spectrum disorders. Vision Res 2009; 49:2140-50. [PMID: 19523974 DOI: 10.1016/j.visres.2009.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 06/05/2009] [Accepted: 06/05/2009] [Indexed: 10/20/2022]
Abstract
In this study, we have used an electrophysiological paradigm to investigate the neural correlates of the visual integration of local signals across space to generate global percepts in a group of low functioning autistic kids. We have analyzed the amplitude of key harmonics of the Visual Evoked Potentials (VEPs) recorded while participants observed orientation-based texture and contour stimuli, forming coherent global patterns, alternating with visual patterns in which the same number of local elements were randomly oriented in order to loose any globally organized feature. Comparing the results of the clinical sample with those obtained in an age-matched control group, we have observed that in the texture conditions the 1st and 3rd harmonics, containing signature of global form processing (Norcia, Pei, Bonneh, Hou, Sampath, & Pettet, 2005), were present in the control group, while in the experimental group only the 1st harmonic was present. In the Contour condition the 1st harmonic was not present for both groups while the 3rd harmonic was significantly present in the control group but absent in the group with autism. Moreover, the amount of organization required to elicit significant 1st harmonic response in the texture condition was higher in the clinical group. The present results bring additional support to the idea that texture and contour processing are supported by independent mechanisms in normal vision. Autistic vision would thus be characterized by a preserved, perhaps weaker texture mechanism, possibly mediated by feedback interactions between visual areas, and by a disfunction of the mechanism supporting contour processing, possibly mediated by long-range intra-cortical connections. Within this framework, the residual ability to detect contours shown in psychophysical studies could be due to the contribution of the texture mechanism to contour processing.
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Affiliation(s)
- Francesca Pei
- Associazione Italiana di Scienze della Visione, Cascina, Pisa, Italy
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