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1. Astroglial-Mediated Remodeling of the Interhemispheric Midline Is Required for the Formation of the Corpus Callosum

Author

Ilan Gobius, Laura Morcom, Rodrigo Suárez, Jens Bunt, Polina Bukshpun, William Reardon, William B. Dobyns, John L.R. Rubenstein, A. James Barkovich, Elliott H. Sherr, and Linda J. Richards

Subjects
astrocyte, callosal agenesis, interhemispheric fissure, Fgf8, Nfia, Nfib, Biology (General), QH301-705.5
Abstract

The corpus callosum is the major axon tract that connects and integrates neural activity between the two cerebral hemispheres. Although ∼1:4,000 children are born with developmental absence of the corpus callosum, the primary etiology of this condition remains unknown. Here, we demonstrate that midline crossing of callosal axons is dependent upon the prior remodeling and degradation of the intervening interhemispheric fissure. This remodeling event is initiated by astroglia on either side of the interhemispheric fissure, which intercalate with one another and degrade the intervening leptomeninges. Callosal axons then preferentially extend over these specialized astroglial cells to cross the midline. A key regulatory step in interhemispheric remodeling is the differentiation of these astroglia from radial glia, which is initiated by Fgf8 signaling to downstream Nfi transcription factors. Crucially, our findings from human neuroimaging studies reveal that developmental defects in interhemispheric remodeling are likely to be a primary etiology underlying human callosal agenesis.

Published
2016
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2. White Matter Changes of Neurite Density and Fiber Orientation Dispersion during Human Brain Maturation.

Author

Yi Shin Chang, Julia P Owen, Nicholas J Pojman, Tony Thieu, Polina Bukshpun, Mari L J Wakahiro, Jeffrey I Berman, Timothy P L Roberts, Srikantan S Nagarajan, Elliott H Sherr, and Pratik Mukherjee

Subjects
Medicine, Science
Abstract

Diffusion tensor imaging (DTI) studies of human brain development have consistently shown widespread, but nonlinear increases in white matter anisotropy through childhood, adolescence, and into adulthood. However, despite its sensitivity to changes in tissue microstructure, DTI lacks the specificity to disentangle distinct microstructural features of white and gray matter. Neurite orientation dispersion and density imaging (NODDI) is a recently proposed multi-compartment biophysical model of brain microstructure that can estimate non-collinear properties of white matter, such as neurite orientation dispersion index (ODI) and neurite density index (NDI). In this study, we apply NODDI to 66 healthy controls aged 7-63 years to investigate changes of ODI and NDI with brain maturation, with comparison to standard DTI metrics. Using both region-of-interest and voxel-wise analyses, we find that NDI exhibits striking increases over the studied age range following a logarithmic growth pattern, while ODI rises following an exponential growth pattern. This novel finding is consistent with well-established age-related changes of FA over the lifespan that show growth during childhood and adolescence, plateau during early adulthood, and accelerating decay after the fourth decade of life. Our results suggest that the rise of FA during the first two decades of life is dominated by increasing NDI, while the fall in FA after the fourth decade is driven by the exponential rise of ODI that overcomes the slower increases of NDI. Using partial least squares regression, we further demonstrate that NODDI better predicts chronological age than DTI. Finally, we show excellent test-retest reliability of NODDI metrics, with coefficients of variation below 5% in all measured regions of interest. Our results support the conclusion that NODDI reveals biologically specific characteristics of brain development that are more closely linked to the microstructural features of white matter than are the empirical metrics provided by DTI.

Published
2015
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3. Both rare and de novo copy number variants are prevalent in agenesis of the corpus callosum but not in cerebellar hypoplasia or polymicrogyria.

Author

Samin A Sajan, Liliana Fernandez, Sahar Esmaeeli Nieh, Eric Rider, Polina Bukshpun, Mari Wakahiro, Susan L Christian, Jean-Baptiste Rivière, Christopher T Sullivan, Jyotsna Sudi, Michael J Herriges, Alexander R Paciorkowski, A James Barkovich, Joseph T Glessner, Kathleen J Millen, Hakon Hakonarson, William B Dobyns, and Elliott H Sherr

Subjects
Genetics, QH426-470
Abstract

Agenesis of the corpus callosum (ACC), cerebellar hypoplasia (CBLH), and polymicrogyria (PMG) are severe congenital brain malformations with largely undiscovered causes. We conducted a large-scale chromosomal copy number variation (CNV) discovery effort in 255 ACC, 220 CBLH, and 147 PMG patients, and 2,349 controls. Compared to controls, significantly more ACC, but unexpectedly not CBLH or PMG patients, had rare genic CNVs over one megabase (p = 1.48×10⁻³; odds ratio [OR] = 3.19; 95% confidence interval [CI] = 1.89-5.39). Rare genic CNVs were those that impacted at least one gene in less than 1% of the combined population of patients and controls. Compared to controls, significantly more ACC but not CBLH or PMG patients had rare CNVs impacting over 20 genes (p = 0.01; OR = 2.95; 95% CI = 1.69-5.18). Independent qPCR confirmation showed that 9.4% of ACC patients had de novo CNVs. These, in comparison to inherited CNVs, preferentially overlapped de novo CNVs previously observed in patients with autism spectrum disorders (p = 3.06×10⁻⁴; OR = 7.55; 95% CI = 2.40-23.72). Interestingly, numerous reports have shown a reduced corpus callosum area in autistic patients, and diminished social and executive function in many ACC patients. We also confirmed and refined previously known CNVs, including significantly narrowing the 8p23.1-p11.1 duplication present in 2% of our current ACC cohort. We found six novel CNVs, each in a single patient, that are likely deleterious: deletions of 1p31.3-p31.1, 1q31.2-q31.3, 5q23.1, and 15q11.2-q13.1; and duplications of 2q11.2-q13 and 11p14.3-p14.2. One ACC patient with microcephaly had a paternally inherited deletion of 16p13.11 that included NDE1. Exome sequencing identified a recessive maternally inherited nonsense mutation in the non-deleted allele of NDE1, revealing the complexity of ACC genetics. This is the first systematic study of CNVs in congenital brain malformations, and shows a much higher prevalence of large gene-rich CNVs in ACC than in CBLH and PMG.

Published
2013
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4. The role of corpus callosum development in functional connectivity and cognitive processing.

Author

Leighton B N Hinkley, Elysa J Marco, Anne M Findlay, Susanne Honma, Rita J Jeremy, Zoe Strominger, Polina Bukshpun, Mari Wakahiro, Warren S Brown, Lynn K Paul, A James Barkovich, Pratik Mukherjee, Srikantan S Nagarajan, and Elliott H Sherr

Subjects
Medicine, Science
Abstract

The corpus callosum is hypothesized to play a fundamental role in integrating information and mediating complex behaviors. Here, we demonstrate that lack of normal callosal development can lead to deficits in functional connectivity that are related to impairments in specific cognitive domains. We examined resting-state functional connectivity in individuals with agenesis of the corpus callosum (AgCC) and matched controls using magnetoencephalographic imaging (MEG-I) of coherence in the alpha (8-12 Hz), beta (12-30 Hz) and gamma (30-55 Hz) bands. Global connectivity (GC) was defined as synchronization between a region and the rest of the brain. In AgCC individuals, alpha band GC was significantly reduced in the dorsolateral pre-frontal (DLPFC), posterior parietal (PPC) and parieto-occipital cortices (PO). No significant differences in GC were seen in either the beta or gamma bands. We also explored the hypothesis that, in AgCC, this regional reduction in functional connectivity is explained primarily by a specific reduction in interhemispheric connectivity. However, our data suggest that reduced connectivity in these regions is driven by faulty coupling in both inter- and intrahemispheric connectivity. We also assessed whether the degree of connectivity correlated with behavioral performance, focusing on cognitive measures known to be impaired in AgCC individuals. Neuropsychological measures of verbal processing speed were significantly correlated with resting-state functional connectivity of the left medial and superior temporal lobe in AgCC participants. Connectivity of DLPFC correlated strongly with performance on the Tower of London in the AgCC cohort. These findings indicate that the abnormal callosal development produces salient but selective (alpha band only) resting-state functional connectivity disruptions that correlate with cognitive impairment. Understanding the relationship between impoverished functional connectivity and cognition is a key step in identifying the neural mechanisms of language and executive dysfunction in common neurodevelopmental and psychiatric disorders where disruptions of callosal development are consistently identified.

Published
2012
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8. Sensorimotor Cortical Oscillations during Movement Preparation in 16p11.2 Deletion Carriers

Author

Corby L. Dale, Srikantan S. Nagarajan, Pratik Mukherjee, Leighton B. Hinkley, Polina Bukshpun, Tracy Luks, Elliott H. Sherr, Wendy K. Chung, Tony Thieu, Jeffrey I. Berman, Timothy P.L. Roberts, Nick Pojman, and Anne M. Findlay

Subjects
magnetoencephalography, Male, speech, Autism, Chromosome Disorders, Medical and Health Sciences, Anticipation, 0302 clinical medicine, 2.1 Biological and endogenous factors, Beta Rhythm, Copy-number variation, Aetiology, Child, Research Articles, 0303 health sciences, medicine.diagnostic_test, General Neuroscience, Magnetoencephalography, Middle Aged, 16p11.2, Mental Health, Neurological, Brain size, Female, Sensorimotor Cortex, Chromosome Deletion, Human, Adult, Heterozygote, Adolescent, Intellectual and Developmental Disabilities (IDD), Sensory system, Biology, Auditory cortex, Basic Behavioral and Social Science, Chromosomes, beta rhythm, 03 medical and health sciences, Clinical Research, Intellectual Disability, Behavioral and Social Science, Genetics, medicine, Humans, Genetic Testing, Autistic Disorder, 030304 developmental biology, Neurology & Neurosurgery, Pair 16, Psychology and Cognitive Sciences, Neurosciences, Motor control, Anticipation, Psychological, medicine.disease, manual, Brain Disorders, Psychological, Neuroscience, Chromosomes, Human, Pair 16, Gene Deletion, 030217 neurology & neurosurgery
Abstract

Sensorimotor deficits are prevalent in many neurodevelopmental disorders like autism, including one of its common genetic etiologies, a 600 kb reciprocal deletion/duplication at 16p11.2. We have previously shown that copy number variations of 16p11.2 impact regional brain volume, white matter integrity, and early sensory responses in auditory cortex. Here, we test the hypothesis that abnormal cortical neurophysiology is present when genes in the 16p11.2 region are haploinsufficient, and in humans that this in turn may account for behavioral deficits specific to deletion carriers. We examine sensorimotor cortical network activity in males and females with 16p11.2 deletions compared with both typically developing individuals, and those with duplications of 16p11.2, using magnetoencephalographic imaging during preparation of overt speech or hand movements in tasks designed to be easy for all participants. In deletion carriers, modulation of beta oscillations (12–30 Hz) were increased during both movement types over effector-specific regions of motor cortices compared with typically developing individuals or duplication carriers, with no task-related performance differences between cohorts, even when corrected for their own cognitive and sensorimotor deficits. Reduced left hemispheric language specialization was observed in deletion carriers but not in duplication carriers. Neural activity over sensorimotor cortices in deletion carriers was linearly related to clinical measures of speech and motor impairment. These findings link insufficient copy number repeats at 16p11.2 to excessive neural activity (e.g., increased beta oscillations) in motor cortical networks for speech and hand motor control. These results have significant implications for understanding the neural basis of autism and related neurodevelopmental disorders. SIGNIFICANCE STATEMENT The recurrent ∼600 kb deletion at 16p11.2 (BP4–BP5) is one of the most common genetic etiologies of ASD and, more generally, of neurodevelopmental disorders. Here, we use high-resolution magnetoencephalographic imaging (MEG-I) to define with millisecond precision the underlying neurophysiological signature of motor impairments for individuals with 16p11.2 deletions. We identify significant increases in beta (12–30 Hz) suppression in sensorimotor cortices related to performance during speech and hand movement tasks. These findings not only provide a neurophysiological phenotype for the clinical presentation of this genetic deletion, but also guide our understanding of how genetic variation encodes for neural oscillatory dynamics.

Published
2019
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9. Brain MR Imaging Findings and Associated Outcomes in Carriers of the Reciprocal Copy Number Variation at 16p11.2

Author

Randy L. Buckner, Orit A. Glenn, Elliott H. Sherr, Jeffrey I. Berman, Timothy P.L. Roberts, Tony Thieu, Debra D'Angelo, Srikantan S. Nagarajan, Polina Bukshpun, Nicholas J. Pojman, Julia P. Owen, Jill V. Hunter, Pratik Mukherjee, Qixuan Chen, and Jihui Lee

Subjects
Adult, Male, 0301 basic medicine, medicine.medical_specialty, Adolescent, DNA Copy Number Variations, Cross-sectional study, Chromosome Disorders, Young Adult, 03 medical and health sciences, symbols.namesake, 0302 clinical medicine, Text mining, Gene Duplication, Intellectual Disability, Internal medicine, medicine, Cluster Analysis, Humans, Radiology, Nuclear Medicine and imaging, Spectrum disorder, Copy-number variation, Autistic Disorder, Young adult, Child, Fisher's exact test, Intelligence quotient, medicine.diagnostic_test, business.industry, Brain, Infant, Magnetic resonance imaging, Middle Aged, Magnetic Resonance Imaging, Cross-Sectional Studies, 030104 developmental biology, Child, Preschool, symbols, Female, Chromosome Deletion, business, Chromosomes, Human, Pair 16, Gene Deletion, 030217 neurology & neurosurgery
Abstract

Purpose To identify developmental neuroradiologic findings in a large cohort of carriers who have deletion and duplication at 16p11.2 (one of the most common genetic causes of autism spectrum disorder [ASD]) and assess how these features are associated with behavioral and cognitive outcomes. Materials and Methods Seventy-nine carriers of a deletion at 16p11.2 (referred to as deletion carriers; age range, 1-48 years; mean age, 12.3 years; 42 male patients), 79 carriers of a duplication at 16p11.2 (referred to as duplication carriers; age range, 1-63 years; mean age, 24.8 years; 43 male patients), 64 unaffected family members (referred to as familial noncarriers; age range, 1-46 years; mean age, 11.7 years; 31 male participants), and 109 population control participants (age range, 6-64 years; mean age, 25.5 years; 64 male participants) were enrolled in this cross-sectional study. Participants underwent structural magnetic resonance (MR) imaging and completed cognitive and behavioral tests. MR images were reviewed for development-related abnormalities by neuroradiologists. Differences in frequency were assessed with a Fisher exact test corrected for multiple comparisons. Unsupervised machine learning was used to cluster radiologic features and an association between clusters and cognitive and behavioral scores from IQ testing, and parental measures of development were tested by using analysis of covariance. Volumetric analysis with automated segmentation was used to confirm radiologic interpretation. Results For deletion carriers, the most prominent features were dysmorphic and thicker corpora callosa compared with familial noncarriers and population control participants (16%; P < .001 and P < .001, respectively) and a greater likelihood of cerebellar tonsillar ectopia (30.7%; P < .002 and P < .001, respectively) and Chiari I malformations (9.3%; P < .299 and P < .002, respectively). For duplication carriers, the most salient findings compared with familial noncarriers and population control participants were reciprocally thinner corpora callosa (18.6%; P < .003 and P < .001, respectively), decreased white matter volume (22.9%; P < .001, and P < .001, respectively), and increased ventricular volume (24.3%; P < .001 and P < .001, respectively). By comparing cognitive assessments to imaging findings, the presence of any imaging feature associated with deletion carriers indicated worse daily living, communication, and social skills compared with deletion carriers without any radiologic abnormalities (P < .005, P < .002, and P < .004, respectively). For the duplication carriers, presence of decreased white matter, callosal volume, and/or increased ventricle size was associated with decreased full-scale and verbal IQ scores compared with duplication carriers without these findings (P < .007 and P < .004, respectively). Conclusion In two genetically related cohorts at high risk for ASD, reciprocal neuroanatomic abnormalities were found and determined to be associated with cognitive and behavioral impairments. © RSNA, 2017 Online supplemental material is available for this article.

Published
2018
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10. Reciprocal white matter alterations due to 16p11.2 chromosomal deletions versus duplications

Author

Jeffrey I. Berman, Wendy K. Chung, Yi Shin Chang, Srikantan S. Nagarajan, Pratik Mukherjee, Randy L. Buckner, Tony Thieu, Polina Bukshpun, Nicholas J. Pojman, Elliott H. Sherr, Timothy P.L. Roberts, John E. Spiro, Mari Wakahiro, Elysa J. Marco, and Julia P. Owen

Subjects
0301 basic medicine, Radiological and Ultrasound Technology, Biology, medicine.disease, Gene dosage, White matter, 03 medical and health sciences, 030104 developmental biology, 0302 clinical medicine, medicine.anatomical_structure, Neurology, Gene duplication, Fractional anisotropy, medicine, Autism, Radiology, Nuclear Medicine and imaging, Neurology (clinical), Copy-number variation, Bipolar disorder, Anatomy, Neuroscience, 030217 neurology & neurosurgery, Diffusion MRI
Abstract

Copy number variants at the 16p11.2 chromosomal locus are associated with several neuropsychiatric disorders, including autism, schizophrenia, bipolar disorder, attention-deficit hyperactivity disorder, and speech and language disorders. A gene dosage dependence has been suggested, with 16p11.2 deletion carriers demonstrating higher body mass index and head circumference, and 16p11.2 duplication carriers demonstrating lower body mass index and head circumference. Here, we use diffusion tensor imaging to elucidate this reciprocal relationship in white matter organization, showing widespread increases of fractional anisotropy throughout the supratentorial white matter in pediatric deletion carriers and, in contrast, extensive decreases of white matter fractional anisotropy in pediatric and adult duplication carriers. We find associations of these white matter alterations with cognitive and behavioral impairments. We further demonstrate the value of imaging metrics for characterizing the copy number variant phenotype by employing linear discriminant analysis to predict the gene dosage status of the study subjects. These results show an effect of 16p11.2 gene dosage on white matter microstructure, and further suggest that opposite changes in diffusion tensor imaging metrics can lead to similar cognitive and behavioral deficits. Given the large effect sizes found in this study, our results support the view that specific genetic variations are more strongly associated with specific brain alterations than are shared neuropsychiatric diagnoses. Hum Brain Mapp 37:2833-2848, 2016. © 2016 Wiley Periodicals, Inc.

Published
2016
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11. Quantifying the effects of 16p11.2 copy number variants on brain structure: A multisite genetic-first study

Author

Sandra Martin-Brevet, Borja Rodríguez-Herreros, Jared A. Nielsen, Clara Moreau, Claudia Modenato, Anne M. Maillard, Aurélie Pain, Sonia Richetin, Aia E. Jønch, Abid Y. Qureshi, Nicole R. Zürcher, Philippe Conus, Wendy K. Chung, Elliott H. Sherr, John E. Spiro, Ferath Kherif, Jacques S. Beckmann, Nouchine Hadjikhani, Alexandre Reymond, Randy L. Buckner, Bogdan Draganski, Sébastien Jacquemont, Marie-Claude Addor, Joris Andrieux, Benoît Arveiler, Geneviève Baujat, Frédérique Sloan-Béna, Marco Belfiore, Dominique Bonneau, Sonia Bouquillon, Odile Boute, Alfredo Brusco, Tiffany Busa, Jean-Hubert Caberg, Dominique Campion, Vanessa Colombert, Marie-Pierre Cordier, Albert David, François-Guillaume Debray, Marie-Ange Delrue, Martine Doco-Fenzy, Ulrike Dunkhase-Heinl, Patrick Edery, Christina Fagerberg, Laurence Faivre, Francesca Forzano, David Genevieve, Marion Gérard, Daniela Giachino, Agnès Guichet, Olivier Guillin, Delphine Héron, Bertrand Isidor, Aurélia Jacquette, Sylvie Jaillard, Hubert Journel, Boris Keren, Didier Lacombe, Sébastien Lebon, Cédric Le Caignec, Marie-Pierre Lemaître, James Lespinasse, Michèle Mathieu-Dramart, Sandra Mercier, Cyril Mignot, Chantal Missirian, Florence Petit, Kristina Pilekær Sørensen, Lucile Pinson, Ghislaine Plessis, Fabienne Prieur, Caroline Rooryck-Thambo, Massimiliano Rossi, Damien Sanlaville, Britta Schlott Kristiansen, Caroline Schluth-Bolard, Marianne Till, Mieke Van Haelst, Lionel Van Maldergem, Hanalore Alupay, Benjamin Aaronson, Sean Ackerman, Katy Ankenman, Ayesha Anwar, Constance Atwell, Alexandra Bowe, Arthur L. Beaudet, Marta Benedetti, Jessica Berg, Jeffrey Berman, Leandra N. Berry, Audrey L. Bibb, Lisa Blaskey, Jonathan Brennan, Christie M. Brewton, Randy Buckner, Polina Bukshpun, Jordan Burko, Phil Cali, Bettina Cerban, Yishin Chang, Maxwell Cheong, Vivian Chow, Zili Chu, Darina Chudnovskaya, Lauren Cornew, Corby Dale, John Dell, Allison G. Dempsey, Trent Deschamps, Rachel Earl, James Edgar, Jenna Elgin, Jennifer Endre Olson, Yolanda L. Evans, Anne Findlay, Gerald D. Fischbach, Charlie Fisk, Brieana Fregeau, Bill Gaetz, Leah Gaetz, Silvia Garza, Jennifer Gerdts, Orit Glenn, Sarah E. Gobuty, Rachel Golembski, Marion Greenup, Kory Heiken, Katherine Hines, Leighton Hinkley, Frank I. Jackson, Julian Jenkins, Rita J. Jeremy, Kelly Johnson, Stephen M. Kanne, Sudha Kessler, Sarah Y. Khan, Matthew Ku, Emily Kuschner, Anna L. Laakman, Peter Lam, Morgan W. Lasala, Hana Lee, Kevin LaGuerre, Susan Levy, Alyss Lian Cavanagh, Ashlie V. Llorens, Katherine Loftus Campe, Tracy L. Luks, Elysa J. Marco, Stephen Martin, Alastair J. Martin, Gabriela Marzano, Christina Masson, Kathleen E. McGovern, Rebecca McNally Keehn, David T. Miller, Fiona K. Miller, Timothy J. Moss, Rebecca Murray, Srikantan S. Nagarajan, Kerri P. Nowell, Julia Owen, Andrea M. Paal, Alan Packer, Patricia Z. Page, Brianna M. Paul, Alana Peters, Danica Peterson, Annapurna Poduri, Nicholas J. Pojman, Ken Porche, Monica B. Proud, Saba Qasmieh, Melissa B. Ramocki, Beau Reilly, Timothy P.L. Roberts, Dennis Shaw, Tuhin Sinha, Bethanny Smith-Packard, Anne Snow Gallagher, Vivek Swarnakar, Tony Thieu, Christina Triantafallou, Roger Vaughan, Mari Wakahiro, Arianne Wallace, Tracey Ward, Julia Wenegrat, Anne Wolken, 16p11.2 European Consortium, Simons Variation in Individuals Project (VIP) Consortium, CSIR-Institute of Microbial Technology [Chandigarh] (IMTech), Council of Scientific and Industrial Research [India] (CSIR), Service Hospitalier Frédéric Joliot (SHFJ), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Human Genetics, Gillberg Neuropsychiatry Centre [Göteborg, Sueden], Institute of Neuroscience and Physiology [Göteborg]-University of Gothenburg (GU), The Wellcome Trust Sanger Institute [Cambridge], Department of Psychiatry [Boston], Massachusetts General Hospital [Boston], Service de génétique médicale, Centre Hospitalier Universitaire Vaudois [Lausanne] (CHUV), Laboratoire de Génétique Clinique, Hôpital Jeanne de Flandre [Lille]-Université de Lille, Droit et Santé-Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille), Laboratoire de Génétique Humaine, Développement et Cancer, Université Bordeaux Segalen - Bordeaux 2, Imagine - Institut des maladies génétiques (IMAGINE - U1163), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), CHU Necker - Enfants Malades [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Service de Génétique Médicale [CHU Necker], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-CHU Necker - Enfants Malades [AP-HP], Guglielmo Marconi University [Roma], Laboratoire de biomécanique (LBM), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Sorbonne Paris Cité (USPC)-Université Paris 13 (UP13), Systèmes de Référence Temps Espace (SYRTE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Service de Génétique clinique, Hôpital Jeanne de Flandre [Lille]-Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille), Department of Medical Sciences, Università degli studi di Torino (UNITO), Marseille medical genetics - Centre de génétique médicale de Marseille (MMG), Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU), Département de génétique médicale [Hôpital de la Timone - APHM], Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)- Hôpital de la Timone [CHU - APHM] (TIMONE)-Institut National de la Santé et de la Recherche Médicale (INSERM), Génétique du cancer et des maladies neuropsychiatriques (GMFC), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Hospitalier Universitaire de Liège (CHU-Liège), Service de cytogénétique constitutionnelle, Hospices Civils de Lyon (HCL)-CHU de Lyon-Centre Neuroscience et Recherche, Department of Clinical Genetics, Vejle Hospital, Institute of Child Health, Département de génétique médicale, maladies rares et médecine personnalisée [CHRU Montpellier], Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Cellules Souches, Plasticité Cellulaire, Médecine Régénératrice et Immunothérapies (IRMB), Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Service de génétique [Angers], Université d'Angers (UA)-Centre Hospitalier Universitaire d'Angers (CHU Angers), PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Nantes Angers Le Mans (UNAM), Génétique médicale et fonctionnelle du cancer et des maladies neuropsychiatriques, Institut de Myologie, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Association française contre les myopathies (AFM-Téléthon)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Service de Génétique Médicale, Centre hospitalier universitaire de Nantes (CHU Nantes), Institut du Cerveau et de la Moëlle Epinière = Brain and Spine Institute (ICM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Institut de recherche en santé, environnement et travail (Irset), Université d'Angers (UA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École des Hautes Études en Santé Publique [EHESP] (EHESP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), CHU Pontchaillou [Rennes], Génétique Médicale, Centre hospitalier Bretagne Atlantique (Morbihan) (CHBA)-Hôpital Chubert, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière (CRICM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-CHU Bordeaux [Bordeaux]-Groupe hospitalier Pellegrin, Physiopathologie et neuroprotection des atteintes du cerveau en développement, Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Département de Génétique Chromosomique, Bâtiment Hôtel Dieu - Centre Hospitalier de Chambéry, CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer - U1172 Inserm - U837 (JPArc), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Lille Nord de France (COMUE)-Université de Lille, Service de génétique, CHU Dijon, Centre Hospitalier Universitaire de Dijon - Hôpital François Mitterrand (CHU Dijon)-Centre Hospitalier Universitaire de Dijon - Hôpital François Mitterrand (CHU Dijon), Service de Génétique [CHU Caen], Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-CHU Caen, Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Tumorothèque de Caen Basse-Normandie (TCBN), Service de Génétique Clinique Chromosomique et Moléculaire, CHU Saint-Etienne, CHU Bordeaux [Bordeaux], Hospices Civils de Lyon (HCL), Centre de recherche en neurosciences de Lyon (CRNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie Moléculaire de la Cellule (LBMC), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Department of Genomics of Common Disease, Imperial College London, Regional Hospital, Department of Psychiatry and Behavioral Sciences! (UW psychiatry), University of Washington [Seattle], University of California, San Francisco (UCSF), UCSF, Unité de Recherches Zootechniques (URZ), Institut National de la Recherche Agronomique (INRA), University of California [San Francisco] (UCSF), University of California, UCL Institute of Neurology, Biomagnetic Imaging Laboratory - University of California, SFARI219193, Simons Foundation, 31003A160203, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Roger De Spoelberch, Partridge Foundations, Jeanne et Jean Louis Levesque Foundation, 604102, Seventh Framework Programme, Canada Research Chairs, CRSII33-133044, SNSF Sinergia, 32003B_159780, SNSF National Centre of Competence in Research Synapsy, Foundation Parkinson Switzerland, Foundation Synapsis, Université de Lausanne = University of Lausanne (UNIL), CHU Sainte Justine [Montréal], Harvard University [Cambridge], Odense University Hospital (OUH), Department of radiology (Massachusetts General Hospital), Department of Psychiatry Massachusetts General Hospital (MGH), Columbia University [New York], Simons Foundation, University of California [San Francisco] (UC San Francisco), University of California (UC), University of Gothenburg (GU), Centre de recherche du CHU Sainte-Justine / Research Center of the Sainte-Justine University Hospital [Montreal, Canada], Université de Montréal (UdeM)-CHU Sainte Justine [Montréal], Université Paris 13 (UP13)-Université Sorbonne Paris Cité (USPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM), Vejle Hospital [Danemark], Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Lille Nord de France (COMUE)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Lille, Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center (CRNL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Harvard University, Université d'Angers (UA)-Université de Rennes (UR)-École des Hautes Études en Santé Publique [EHESP] (EHESP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer - U837 (JPArc), Centre Hospitalier Universitaire de Saint-Etienne [CHU Saint-Etienne] (CHU ST-E), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), University of Lausanne (UNIL), Centre de recherche du CHU Sainte-Justine [Montreal], Institut National de la Santé et de la Recherche Médicale (INSERM)- Hôpital de la Timone [CHU - APHM] (TIMONE)-Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU), CHU Caen, Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Amsterdam Neuroscience - Complex Trait Genetics, Amsterdam Reproduction & Development (AR&D), Human genetics, Institute of Microbial Technology (IMTECH), Intitute of Microbial Technology, Gillberg Neuropsychiatry Centre, Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-CHU Necker - Enfants Malades [AP-HP], PSL Research University (PSL)-PSL Research University (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Département de génétique médicale, maladies rares et médecine personnalisée [CHRU de Montpellier], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Association française contre les myopathies (AFM-Téléthon)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-CHU Pitié-Salpêtrière [APHP], Centre Hospitalier Bretagne Atlantique-Hôpital Chubert, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC), CHU Pitié-Salpêtrière [APHP], Centre de recherche Jean-Pierre Aubert-Neurosciences et Cancer, Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Lille, Droit et Santé, Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Addor, M.C., Andrieux, J., Arveiler, B., Baujat, G., Sloan-Béna, F., Belfiore, M., Bonneau, D., Bouquillon, S., Boute, O., Brusco, A., Busa, T., Caberg, J.H., Campion, D., Colombert, V., Cordier, M.P., David, A., Debray, F.G., Delrue, M.A., Doco-Fenzy, M., Dunkhase-Heinl, U., Edery, P., Fagerberg, C., Faivre, L., Forzano, F., Genevieve, D., Gérard, M., Giachino, D., Guichet, A., Guillin, O., Héron, D., Isidor, B., Jacquette, A., Jaillard, S., Journel, H., Keren, B., Lacombe, D., Lebon, S., Le Caignec, C., Lemaître, M.P., Lespinasse, J., Mathieu-Dramart, M., Mercier, S., Mignot, C., Missirian, C., Petit, F., Pilekær Sørensen, K., Pinson, L., Plessis, G., Prieur, F., Rooryck-Thambo, C., Rossi, M., Sanlaville, D., Schlott Kristiansen, B., Schluth-Bolard, C., Till, M., Van Haelst, M., Van Maldergem, L., Alupay, H., Aaronson, B., Ackerman, S., Ankenman, K., Anwar, A., Atwell, C., Bowe, A., Beaudet, A.L., Benedetti, M., Berg, J., Berman, J., Berry, L.N., Bibb, A.L., Blaskey, L., Brennan, J., Brewton, C.M., Buckner, R., Bukshpun, P., Burko, J., Cali, P., Cerban, B., Chang, Y., Cheong, M., Chow, V., Chu, Z., Chudnovskaya, D., Cornew, L., Dale, C., Dell, J., Dempsey, A.G., Deschamps, T., Earl, R., Edgar, J., Elgin, J., Olson, J.E., Evans, Y.L., Findlay, A., Fischbach, G.D., Fisk, C., Fregeau, B., Gaetz, B., Gaetz, L., Garza, S., Gerdts, J., Glenn, O., Gobuty, S.E., Golembski, R., Greenup, M., Heiken, K., Hines, K., Hinkley, L., Jackson, F.I., Jenkins, J., Jeremy, R.J., Johnson, K., Kanne, S.M., Kessler, S., Khan, S.Y., Ku, M., Kuschner, E., Laakman, A.L., Lam, P., Lasala, M.W., Lee, H., LaGuerre, K., Levy, S., Cavanagh, A.L., Llorens, A.V., Campe, K.L., Luks, T.L., Marco, E.J., Martin, S., Martin, A.J., Marzano, G., Masson, C., McGovern, K.E., McNally Keehn, R., Miller, D.T., Miller, F.K., Moss, T.J., Murray, R., Nagarajan, S.S., Nowell, K.P., Owen, J., Paal, A.M., Packer, A., Page, P.Z., Paul, B.M., Peters, A., Peterson, D., Poduri, A., Pojman, N.J., Porche, K., Proud, M.B., Qasmieh, S., Ramocki, M.B., Reilly, B., Roberts, TPL, Shaw, D., Sinha, T., Smith-Packard, B., Gallagher, A.S., Swarnakar, V., Thieu, T., Triantafallou, C., Vaughan, R., Wakahiro, M., Wallace, A., Ward, T., Wenegrat, J., and Wolken, A.

Subjects
Adult, Male, 0301 basic medicine, Adolescent, DNA Copy Number Variations, [SDV]Life Sciences [q-bio], Autism Spectrum Disorder/diagnostic imaging, Autism Spectrum Disorder/genetics, Brain/pathology, Child, Chromosome Deletion, Chromosome Duplication, Chromosomes, Human, Pair 16/genetics, Cognitive Dysfunction/diagnostic imaging, Cognitive Dysfunction/genetics, Female, Humans, Intellectual Disability/diagnostic imaging, Intellectual Disability/genetics, Language, Magnetic Resonance Imaging, Middle Aged, Neurodevelopmental Disorders/diagnostic imaging, Neurodevelopmental Disorders/genetics, Schizophrenia/diagnostic imaging, Schizophrenia/genetics, Young Adult, 16p11.2, Autism spectrum disorder, Copy number variant, Genetics, Imaging, Neurodevelopmental disorders, Biology, Biological Psychiatry, 03 medical and health sciences, 0302 clinical medicine, Transverse temporal gyrus, Neuroimaging, Intellectual Disability, medicine, Cognitive Dysfunction, Copy-number variation, ComputingMilieux_MISCELLANEOUS, Brain morphometry, Brain, medicine.disease, 16p112, 030104 developmental biology, Schizophrenia, Williams syndrome, Neuroscience, Insula, Chromosomes, Human, Pair 16, 030217 neurology & neurosurgery
Abstract

BACKGROUND: 16p11.2 breakpoint 4 to 5 copy number variants (CNVs) increase the risk for developing autism spectrum disorder, schizophrenia, and language and cognitive impairment. In this multisite study, we aimed to quantify the effect of 16p11.2 CNVs on brain structure.METHODS: Using voxel- and surface-based brain morphometric methods, we analyzed structural magnetic resonance imaging collected at seven sites from 78 individuals with a deletion, 71 individuals with a duplication, and 212 individuals without a CNV.RESULTS: Beyond the 16p11.2-related mirror effect on global brain morphometry, we observe regional mirror differences in the insula (deletion > control > duplication). Other regions are preferentially affected by either the deletion or the duplication: the calcarine cortex and transverse temporal gyrus (deletion > control; Cohen's d > 1), the superior and middle temporal gyri (deletion < control; Cohen's d < -1), and the caudate and hippocampus (control > duplication; -0.5 > Cohen's d > -1). Measures of cognition, language, and social responsiveness and the presence of psychiatric diagnoses do not influence these results.CONCLUSIONS: The global and regional effects on brain morphometry due to 16p11.2 CNVs generalize across site, computational method, age, and sex. Effect sizes on neuroimaging and cognitive traits are comparable. Findings partially overlap with results of meta-analyses performed across psychiatric disorders. However, the lack of correlation between morphometric and clinical measures suggests that CNV-associated brain changes contribute to clinical manifestations but require additional factors for the development of the disorder. These findings highlight the power of genetic risk factors as a complement to studying groups defined by behavioral criteria.

Published
2018
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12. Aberrant White Matter Microstructure in Children with 16p11.2 Deletions

Author

John E. Spiro, Srikantan S. Nagarajan, Elliott H. Sherr, Polina Bukshpun, Nicholas J. Pojman, Elysa J. Marco, Jeffrey I. Berman, Wendy K. Chung, Randy L. Buckner, Pratik Mukherjee, Yi Shin Chang, Julia P. Owen, Timothy P.L. Roberts, and Mari Wakahiro

Subjects
Male, Adolescent, Models, Neurological, Statistics as Topic, Biophysics, Chromosome Disorders, Locus (genetics), Biology, Corpus callosum, Nerve Fibers, Myelinated, White matter, Leukoencephalopathies, Intellectual Disability, Fractional anisotropy, Image Processing, Computer-Assisted, medicine, Humans, Copy-number variation, Autistic Disorder, Child, Genetics, medicine.diagnostic_test, General Neuroscience, Brain, Magnetic resonance imaging, Articles, medicine.disease, Diffusion Magnetic Resonance Imaging, medicine.anatomical_structure, Case-Control Studies, Anisotropy, Autism, Female, Chromosome Deletion, Cognition Disorders, Chromosomes, Human, Pair 16, Diffusion MRI
Abstract

Copy number variants (CNVs) of the chromosomal locus 16p11.2, consisting of either deletions or duplications, have been implicated in autism, schizophrenia, epilepsy, and other neuropsychiatric disorders. Since abnormal white matter microstructure can be seen in these more broadly defined clinical disorders, we used diffusion magnetic resonance imaging and tract-based spatial statistics to investigate white matter microstructural integrity in human children with 16p11.2 deletions. We show that deletion carriers, compared with typically developing matched controls, have increased axial diffusivity (AD) in many major central white matter tracts, including the anterior corpus callosum as well as bilateral internal and external capsules. Higher AD correlated with lower nonverbal IQ in the deletion carriers, but not controls. Increases in fractional anisotropy and mean diffusivity were also found in some of the same tracts with elevated AD. Closer examination with neurite orientation dispersion and density imaging revealed that fiber orientation dispersion was decreased in some central white matter tracts. Notably, these alterations of white matter are unlike microstructural differences reported for any other neurodevelopmental disorders, including autism spectrum disorders that have phenotypic overlap with the deletion carriers. These findings suggest that deletion of the 16p11.2 locus is associated with a unique widespread pattern of aberrant white matter microstructure that may underlie the impaired cognition characteristic of this CNV.

Published
2014
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13. The Contribution of the Corpus Callosum to Language Lateralization

Author

Polina Bukshpun, Jacquelyn Gold, Elliott H. Sherr, Elysa J. Marco, Srikantan S. Nagarajan, Rita J. Jeremy, Leighton B. Hinkley, Mari Wakahiro, Pratik Mukherjee, Anne M. Findlay, Ethan G. Brown, Susanna S. Hill, and A. James Barkovich

Subjects
Adult, Male, magnetoencephalography, medicine.medical_specialty, Adolescent, Audiology, Corpus callosum, Medical and Health Sciences, 050105 experimental psychology, Lateralization of brain function, Functional Laterality, Developmental psychology, Corpus Callosum, Cohort Studies, 03 medical and health sciences, Young Adult, 0302 clinical medicine, Clinical Research, medicine, Humans, Speech, 0501 psychology and cognitive sciences, Agenesis of the corpus callosum, Language, language, Neurology & Neurosurgery, General Neuroscience, hemispheric specialization, 05 social sciences, Functional specialization, Psychology and Cognitive Sciences, Magnetoencephalography, Articles, Middle Aged, medicine.disease, Verbal reasoning, Acoustic Stimulation, Agenesis, Laterality, Female, Agenesis of Corpus Callosum, Psychology, 030217 neurology & neurosurgery, Neurotypical, Psychomotor Performance
Abstract

The development of hemispheric lateralization for language is poorly understood. In one hypothesis, early asymmetric gene expression assigns language to the left hemisphere. In an alternate view, language is represented a priori in both hemispheres and lateralization emerges via cross-hemispheric communication through the corpus callosum. To address this second hypothesis, we capitalized on the high temporal and spatial resolution of magnetoencephalographic imaging to measure cortical activity during language processing, speech preparation, and speech execution in 25 participants with agenesis of the corpus callosum (AgCC) and 21 matched neurotypical individuals. In contrast to strongly lateralized left hemisphere activations for language in neurotypical controls, participants with complete or partial AgCC exhibited bilateral hemispheric activations in both auditory or visually driven language tasks, with complete AgCC participants showing significantly more right hemisphere activations than controls or than individuals with partial AgCC. In AgCC individuals, language laterality positively correlated with verbal IQ. These findings suggest that the corpus callosum helps to drive language lateralization.SIGNIFICANCE STATEMENTThe role that corpus callosum development has on the hemispheric specialization of language is poorly understood. Here, we used magnetoencephalographic imaging during linguistic tests (verb generation, picture naming) to test for hemispheric dominance in patients with agenesis of the corpus callosum (AgCC) and found reduced laterality (i.e., greater likelihood of bilaterality or right hemisphere dominance) in this cohort compared with controls, especially in patients with complete agenesis. Laterality was positively correlated with behavioral measures of verbal intelligence. These findings provide support for the hypothesis that the callosum aids in functional specialization throughout neural development and that the loss of this mechanism correlates with impairments in verbal performance.

Published
2016

14. Autism Traits in Individuals with Agenesis of the Corpus Callosum

Author

Polina Bukshpun, Zoe Strominger, Mari Wakahiro, Elliott H. Sherr, Leighton B. Hinkley, Elysa J. Marco, Srikantan S. Nagarajan, Simon Baron-Cohen, Rita J. Jeremy, Yolanda C. Lau, Bonnie Auyeung, and Carrie Allison

Subjects
Male, Autism-spectrum quotient, Autism, Audiology, Corpus callosum, Functional connectivity, Superior temporal gyrus, Surveys and Questionnaires, Developmental and Educational Psychology, 2.1 Biological and endogenous factors, Aetiology, Child, Agenesis of the corpus callosum, Pediatric, medicine.diagnostic_test, Magnetoencephalography, Autism spectrum disorders, Magnetic Resonance Imaging, Fragile X syndrome, Mental Health, Child, Preschool, Cohort, Biomedical Imaging, Female, Psychology, Adult, medicine.medical_specialty, Child Development Disorders, Adolescent, Intellectual and Developmental Disabilities (IDD), 1.1 Normal biological development and functioning, Developmental & Child Psychology, behavioral disciplines and activities, Autism Spectrum Quotient, Article, Education, Clinical Research, Underpinning research, Behavioral and Social Science, mental disorders, medicine, Humans, Preschool, Psychiatry, Pervasive, Psychology and Cognitive Sciences, Neurosciences, medicine.disease, Brain Disorders, Child Development Disorders, Pervasive, Agenesis of Corpus Callosum
Abstract

Autism spectrum disorders (ASD) have numerous etiologies, including structural brain malformations such as agenesis of the corpus callosum (AgCC). We sought to directly measure the occurrence of autism traits in a cohort of individuals with AgCC and to investigate the neural underpinnings of this association. We screened a large AgCC cohort (n=106) with the Autism Spectrum Quotient (AQ) and found that 45% of children, 35% of adolescents, and 18% of adults exceeded the predetermined autism-screening cut-off. Interestingly, performance on the AQ's imagination domain was inversely correlated with magnetoencephalography measures of resting-state functional connectivity in the right superior temporal gyrus. Individuals with AgCC should be screened for ASD and disorders of the corpus callosum should be considered in autism diagnostic evaluations as well.

Published
2012
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15. A 600 kb deletion syndrome at 16p11.2 leads to energy imbalance and neuropsychiatric disorders

Author

Laurent Pasquier, Anne V. Snow, David T. Miller, Louise Harewood, Christina Triantafallou, Timothy P.L. Roberts, Leighton B. Hinkley, Zili Chu, Louis Vallée, Alyss Lian Cavanagh, Evica Rajcan-Separovic, Patricia Blanchet, Fiona Miller, Robin P. Goin-Kochel, Beau Reilly, Bettina Cerban, Vanessa Siffredi, Bridget A. Fernandez, Roger Vaughan, Brianna M. Paul, Fanny Morice-Picard, Elisabeth Flori, Dominique Campion, Gérard Didelot, Anne Philippe, Christa Lese Martin, Srikantan S. Nagarajan, Joris Andrieux, Jacques Puechberty, Marie Pierre Cordier, Jill V. Hunter, Ellen van Binsbergen, Catherine Vincent-Delorme, Vivek Swarnakar, Jean Marie Cuisset, Monica Proud, Patrick Callier, Bert B.A. de Vries, Jeffrey I. Berman, Sarah J. Spence, Alexandra Bowe, Wendy K. Chung, Katy Ankenman, Katherine Hines, Sarah E. Gobuty, Philippe Jonveaux, Lisa Blaskey, Alice Goldenberg, Sylvie Jaillard, Alessandra Renieri, Anne M. Maillard, Tracy Luks, Lee Anne Green Snyder, Elliott H. Sherr, Sarah Y. Khan, Fabienne Prieur, Simon A. Zwolinski, Andres Metspalu, Ghislaine Plessis, Jean Chiesa, Rita J. Jeremy, Valérie Malan, Michèle Mathieu-Dramard, Loyse Hippolyte, Bethanny Smith-Packard, Andrea M. Paal, Bénédicte Duban Bedu, Claudine Rieubland, Jordan Burko, Sylvie Joriot, Philippe Conus, Dominique Bonneau, Benoit Arveiler, Nicole de Leeuw, Allison G. Dempsey, John E. Spiro, Julia Wenegrat, Bertrand Isidor, Cédric Le Caignec, Kyle J. Steinman, Bruno Delobel, Ashlie Llorens, Jacques S. Beckmann, Kelly Johnson, Sean Ackerman, Polina Bukshpun, Silvia Garza, Alexandre Reymond, Damien Sanlaville, Ellen Hanson, Martine Doco-Fenzy, Jacques Thonney, Mari Wakahiro, Juliane Hoyer, Jacqueline Vigneron, Katrin Õunap, Arthur L. Beaudet, Mandy Barker, Nicole Visyak, Sonia Bouquillon, W. Andrew Faucett, Raphael Bernier, Sudha Kilaru Kessler, Audrey Lynn Bibb, Dennis Shaw, R. Frank Kooy, Suzanne M E Lewis, Anna L. Laakman, Nicholas J. Pojman, Hubert Journel, Laura Bernardini, Arianne Stevens, Julia P. Owen, Rebecca Mc Nally Keehn, Stéphanie Selmoni, Sébastien Lebon, Aurélien Macé, Bruno Leheup, Saba Qasmieh, Zoltán Kutalik, Anita Rauch, Yiping Shen, Elysa J. Marco, Nathalie Van der Aa, Carina Ferrari, Noam D. Beckmann, Delphine Héron, Jennifer Tjernage, Benjamin Aaronson, Albert David, Marie Pierre Lemaitre, Muriel Holder, Eve Õiglane-Shlik, Anneke T. Vulto-van Silfhout, Flore Zufferey, Constance Atwell, Marta Benedetti, Ellen Grant, Jenna Elgin, Patricia Z. Page, Caroline Rooryck, Randy L. Buckner, Qixuan Chen, Laurence Faivre, Sébastien Jacquemont, Kerri P. Nowell, Florence Fellmann, Disciglio Vittoria, Katharina Magdalena Rötzer, Hana Lee, Alastair J. Martin, Marion Greenup, David H. Ledbetter, Katrin Männik, Morgan W. Lasala, Jennifer Gerdts, Hanalore Alupay, Florence Petit, Elizabeth Aylward, Gerald D. Fischbach, Mafalda Mucciolo, Maxwell Cheong, Gabriela Marzano, Frédérique Béna, Danielle Martinet, Timothy J. Moss, Odile Boute, Jennifer Olson, Marco Belfiore, Christina Fagerberg, Corby L. Dale, Robert M. Witwicki, Yolanda L. Evans, Melissa B. Ramocki, Marie-Claude Addor, Christèle Dubourg, Mariken Ruiter, Tuhin K. Sinha, Mieke M. van Haelst, Alan Packer, Kathleen E. McGovern, Christie M. Brewton, Stephen M. Kanne, Richard I. Fisher, Tracey Ward, Sophie Dupuis-Girod, Pratik Mukherjee, Simons VIP Consortium, 16p11.2 European Consortium, Addor, MC., Arveiler, B., Belfiore, M., Bena, F., Bernardini, L., Blanchet, P., Bonneau, D., Boute, O., Callier, P., Campion, D., Chiesa, J., Cordier, MP., Cuisset, JM., David, A., de Leeuw, N., de Vries, B., Didelot, G., Doco-Fenzy, M., Bedu, BD., Dubourg, C., Dupuis-Girod, S., Fagerberg, CR., Faivre, L., Fellmann, F., Fernandez, BA., Fisher, R., Flori, E., Goldenberg, A., Heron, D., Holder, M., Hoyer, J., Isidor, B., Jaillard, S., Jonveaux, P., Joriot, S., Journel, H., Kooy, F., le Caignec, C., Leheup, B., Lemaitre, MP., Lewis, S., Malan, V., Mathieu-Dramard, M., Metspalu, A., Morice-Picard, F., Mucciolo, M., Oiglane-Shlik, E., Ounap, K., Pasquier, L., Petit, F., Philippe, A., Plessis, G., Prieur, F., Puechberty, J., Rajcan-Separovic, E., Rauch, A., Renieri, A., Rieubland, C., Rooryck, C., Rötzer, KM., Ruiter, M., Sanlaville, D., Selmoni, S., Shen, Y., Siffredi, V., Thonney, J., Vallée, L., van Binsbergen, E., Van der Aa, N., van Haelst MM., Vigneron, J., Vincent-Delorme, C., Vittoria, D., Vulto-van Silfhout AT., Witwicki, RM., Zwolinski, SA., Bowe, A., Beaudet, AL., Brewton, CM., Chu, Z., Dempsey, AG., Evans, YL., Garza, S., Kanne, SM., Laakman, AL., Lasala, MW., Llorens, AV., Marzano, G., Moss, TJ., Nowell, KP., Proud, MB., Chen, Q., Vaughan, R., Berman, J., Blaskey, L., Hines, K., Kessler, S., Khan, SY., Qasmieh, S., Bibb, AL., Paal, AM., Page, PZ., Smith-Packard, B., Buckner, R., Burko, J., Cavanagh, AL., Cerban, B., Snow, AV., Snyder, LG., Keehn, RM., Miller, DT., Miller, FK., Olson, JE., Triantafallou, C., Visyak, N., Atwell, C., Benedetti, M., Fischbach, GD., Greenup, M., Packer, A., Bukshpun, P., Cheong, M., Dale, C., Gobuty, SE., Hinkley, L., Jeremy, RJ., Lee, H., Luks, TL., Marco, EJ., Martin, AJ., McGovern, KE., Nagarajan, SS., Owen, J., Paul, BM., Pojman, NJ., Sinha, T., Swarnakar, V., Wakahiro, M., Alupay, H., Aaronson, B., Ackerman, S., Ankenman, K., Elgin, J., Gerdts, J., Johnson, K., Reilly, B., Shaw, D., Stevens, A., Ward, T., Wenegrat, J., Other departments, Service de génétique médicale, Centre Hospitalier Universitaire Vaudois [Lausanne] (CHUV), CHU Pontchaillou [Rennes], Department of Medical Genetics, Université de Lausanne (UNIL), Centre de Génétique Chromosomique, Hôpital Saint Vincent de Paul-GHICL, Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Baylor University-Baylor University, Texas Children's Hospital [Houston, USA], Department of pediatrics, Primary palliative Care Research Group, Community Health Sciences, General Practice Section, University of Edinburgh, Center for Integrative Genomics - Institute of Bioinformatics, Génopode (CIG), Swiss Institute of Bioinformatics [Lausanne] (SIB), Université de Lausanne (UNIL)-Université de Lausanne (UNIL), Physiopathologie et neuroprotection des atteintes du cerveau en développement, Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Developmental Brain and Behaviour Unit, University of Southampton, Institute of Molecular and Cell Biology, University of Tartu, Department of Human Genetics, UCLA, University of California [Los Angeles] (UCLA), University of California-University of California-Semel Institute, Institut de Génétique et Développement de Rennes (IGDR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Service de Cytogénétique et de Biologie Cellulaire, Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Hôpital Pontchaillou-CHU Pontchaillou [Rennes], Université de Lausanne = University of Lausanne (UNIL), Hôpital Saint Vincent de Paul-Groupement des Hôpitaux de l'Institut Catholique de Lille (GHICL), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Université de Lausanne = University of Lausanne (UNIL)-Université de Lausanne = University of Lausanne (UNIL), University of California (UC)-University of California (UC)-Semel Institute, Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Université de Rennes (UR)-Hôpital Pontchaillou-CHU Pontchaillou [Rennes], and Kooy, Frank

Subjects
Adult, Male, Pediatrics, medicine.medical_specialty, Heterozygote, Adolescent, [SDV]Life Sciences [q-bio], Developmental Disabilities, Biology, Body Mass Index, 03 medical and health sciences, Young Adult, 0302 clinical medicine, Gene Order, Genetics, medicine, Humans, Copy-number variation, Clinical genetics, Obesity, Young adult, Child, Genetics (clinical), 030304 developmental biology, Child Development Disorders, Pervasive/diagnosis, Child Development Disorders, Pervasive/genetics, Chromosome Deletion, Chromosomes, Human, Pair 16, Developmental Disabilities/diagnosis, Developmental Disabilities/genetics, Female, Intelligence Tests, Phenotype, Syndrome, 2. Zero hunger, Psychiatry, 0303 health sciences, Intelligence quotient, Neuropsychology, Complex traits, medicine.disease, Comorbidity, 3. Good health, Autism spectrum disorder, Child Development Disorders, Pervasive, Autism, Medical genetics, Human medicine, Copy-Number Variation, 030217 neurology & neurosurgery
Abstract

Background The recurrent ∼600 kb 16p11.2 BP4-BP5 deletion is among the most frequent known genetic aetiologies of autism spectrum disorder (ASD) and related neurodevelopmental disorders. Objective To define the medical, neuropsychological, and behavioural phenotypes in carriers of this deletion. Methods We collected clinical data on 285 deletion carriers and performed detailed evaluations on 72 carriers and 68 intrafamilial non-carrier controls. Results When compared to intrafamilial controls, full scale intelligence quotient (FSIQ) is two standard deviations lower in carriers, and there is no difference between carriers referred for neurodevelopmental disorders and carriers identified through cascade family testing. Verbal IQ (mean 74) is lower than non-verbal IQ (mean 83) and a majority of carriers require speech therapy. Over 80% of individuals exhibit psychiatric disorders including ASD, which is present in 15% of the paediatric carriers. Increase in head circumference (HC) during infancy is similar to the HC and brain growth patterns observed in idiopathic ASD. Obesity, a major comorbidity present in 50% of the carriers by the age of 7 years, does not correlate with FSIQ or any behavioural trait. Seizures are present in 24% of carriers and occur independently of other symptoms. Malformations are infrequently found, confirming only a few of the previously reported associations. Conclusions The 16p11.2 deletion impacts in a quantitative and independent manner FSIQ, behaviour and body mass index, possibly through direct influences on neural circuitry. Although non-specific, these features are clinically significant and reproducible. Lastly, this study demonstrates the necessity of studying large patient cohorts ascertained through multiple methods to characterise the clinical consequences of rare variants involved in common diseases.

Published
2012
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16. Genetic and functional analyses identify DISC1 as a novel callosal agenesis candidate gene

Author

Eric Rider, Elliott H. Sherr, Mari Wakahiro, Zoe Strominger, Graeme C.M. Black, Jiang Li, Polina Bukshpun, Mary O'Driscoll, William B. Dobyns, Elena Boland, Cailyn H. Spurrell, Nathan C. Osbun, Wendy Schackwitz, and Len A. Pennacchio

Subjects
Male, Candidate gene, Adolescent, Molecular Sequence Data, Mutation, Missense, Nerve Tissue Proteins, Genome-wide association study, Biology, Corpus callosum, Polymorphism, Single Nucleotide, Article, Corpus Callosum, Mice, Exon, DISC1, Genetics, medicine, Animals, Humans, Abnormalities, Multiple, Amino Acid Sequence, Child, Agenesis of the corpus callosum, Genetics (clinical), Chromosomal Deletion, Splice site mutation, Sequence Analysis, DNA, medicine.disease, Chromosomes, Human, Pair 1, Child, Preschool, biology.protein, Female, Wolff-Parkinson-White Syndrome, Agenesis of Corpus Callosum, Chromosome Deletion, Sequence Alignment, Genome-Wide Association Study
Abstract

Agenesis of the corpus callosum (AgCC) is a congenital brain malformation that occurs in approximately 1:1,000-1:6,000 births. Several syndromes associated with AgCC have been traced to single gene mutations; however, the majority of AgCC causes remain unidentified. We investigated a mother and two children who all shared complete AgCC and a chromosomal deletion at 1q42. We fine mapped this deletion and show that it includes Disrupted-in-Schizophrenia 1 (DISC1), a gene implicated in schizophrenia and other psychiatric disorders. Furthermore, we report a de novo chromosomal deletion at 1q42.13 to q44, which includes DISC1, in another individual with AgCC. We resequenced DISC1 in a cohort of 144 well-characterized AgCC individuals and identified 20 sequence changes, of which 4 are rare potentially pathogenic variants. Two of these variants were undetected in 768 control chromosomes. One of these is a splice site mutation at the 5' boundary of exon 11 that dramatically reduces full-length mRNA expression of DISC1, but not of shorter forms. We investigated the developmental expression of mouse DISC1 and find that it is highly expressed in the embryonic corpus callosum at a critical time for callosal formation. Taken together our results suggest a significant role for DISC1 in corpus callosum development.

Published
2011
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17. Reciprocal white matter alterations due to 16p11.2 chromosomal deletions versus duplications

Author

Yi Shin, Chang, Julia P, Owen, Nicholas J, Pojman, Tony, Thieu, Polina, Bukshpun, Mari L J, Wakahiro, Elysa J, Marco, Jeffrey I, Berman, John E, Spiro, Wendy K, Chung, Randy L, Buckner, Timothy P L, Roberts, Srikantan S, Nagarajan, Elliott H, Sherr, and Pratik, Mukherjee

Subjects
Adult, Male, Heterozygote, Adolescent, Gene Dosage, Brain, Middle Aged, White Matter, Young Adult, Diffusion Tensor Imaging, Chromosome Duplication, Humans, Female, Chromosome Deletion, Child, Chromosomes, Human, Pair 16, Research Articles
Abstract

Copy number variants at the 16p11.2 chromosomal locus are associated with several neuropsychiatric disorders, including autism, schizophrenia, bipolar disorder, attention‐deficit hyperactivity disorder, and speech and language disorders. A gene dosage dependence has been suggested, with 16p11.2 deletion carriers demonstrating higher body mass index and head circumference, and 16p11.2 duplication carriers demonstrating lower body mass index and head circumference. Here, we use diffusion tensor imaging to elucidate this reciprocal relationship in white matter organization, showing widespread increases of fractional anisotropy throughout the supratentorial white matter in pediatric deletion carriers and, in contrast, extensive decreases of white matter fractional anisotropy in pediatric and adult duplication carriers. We find associations of these white matter alterations with cognitive and behavioral impairments. We further demonstrate the value of imaging metrics for characterizing the copy number variant phenotype by employing linear discriminant analysis to predict the gene dosage status of the study subjects. These results show an effect of 16p11.2 gene dosage on white matter microstructure, and further suggest that opposite changes in diffusion tensor imaging metrics can lead to similar cognitive and behavioral deficits. Given the large effect sizes found in this study, our results support the view that specific genetic variations are more strongly associated with specific brain alterations than are shared neuropsychiatric diagnoses. Hum Brain Mapp 37:2833–2848, 2016. © 2016 Wiley Periodicals, Inc.

Published
2015

18. Resting-state networks and the functional connectome of the human brain in agenesis of the corpus callosum

Author

Srikantan S. Nagarajan, Yi-Ou Li, Polina Bukshpun, Julia P. Owen, Fanpei Gloria Yang, Pratik Mukherjee, Charvi Shetty, Shivani Vora, Mari Wakahiro, Leighton B. Hinkley, and Elliott H. Sherr

Subjects
Adult, Male, Adolescent, graph theory, brain development, Corpus callosum, Basic Behavioral and Social Science, White matter, corpus callosum, Dysgenesis, Young Adult, Behavioral and Social Science, medicine, Connectome, Humans, 2.1 Biological and endogenous factors, Prospective Studies, Aetiology, Agenesis of the corpus callosum, Cerebral Cortex, medicine.diagnostic_test, Resting state fMRI, General Neuroscience, fMRI, Neurosciences, Original Articles, Human brain, medicine.disease, Magnetic Resonance Imaging, Oxygen, medicine.anatomical_structure, Case-Control Studies, connectivity, Neurological, malformations, Female, Nerve Net, Agenesis of Corpus Callosum, Functional magnetic resonance imaging, Psychology, Neuroscience, white matter
Abstract

The corpus callosum is the largest white matter fiber bundle connecting the two cerebral hemispheres. In this work, we investigate the effect of callosal dysgenesis on functional magnetic resonance imaging (fMRI) resting-state networks and the functional connectome. Since alternate commissural routes between the cerebral hemispheres exist, we hypothesize that bilateral cortical networks can still be maintained in partial or even complete agenesis of the corpus callosum (AgCC). However, since these commissural routes are frequently indirect, requiring polysynaptic pathways, we hypothesize that quantitative measurements of interhemispheric functional connectivity in bilateral networks will be reduced in AgCC compared with matched controls, especially in the most highly interconnected cortical regions that are the hubs of the connectome. Seventeen resting-state networks were extracted from fMRI of 11 subjects with partial or complete AgCC and 11 matched controls. The results show that the qualitative organization of resting-state networks is very similar between controls and AgCC. However, interhemispheric functional connectivity of precuneus, posterior cingulate cortex, and insular-opercular regions was significantly reduced in AgCC. The preserved network organization was confirmed with a connectomic analysis of the resting-state fMRI data, showing five functional modules that are largely consistent across the control and AgCC groups. Hence, the reduction or even complete absence of callosal connectivity does not affect the qualitative organization of bilateral resting-state networks or the modular organization of the functional connectome, although quantitatively reduced functional connectivity can be demonstrated by measurements within bilateral cortical hubs, supporting the hypothesis that indirect polysynaptic pathways are utilized to preserve interhemispheric temporal synchrony.

Published
2013

19. The role of corpus callosum development in functional connectivity and cognitive processing

Author

Anne M. Findlay, Polina Bukshpun, Pratik Mukherjee, A. James Barkovich, Rita J. Jeremy, Mari Wakahiro, Warren S. Brown, Leighton B. Hinkley, Lynn K. Paul, Elliott H. Sherr, Zoe Strominger, Elysa J. Marco, Susanne M. Honma, Srikantan S. Nagarajan, and Maurits, Natasha M

Subjects
Male, lcsh:Medicine, Corpus callosum, Corpus Callosum, Behavioral Neuroscience, 0302 clinical medicine, Cognition, 2.1 Biological and endogenous factors, Aetiology, Agenesis of the corpus callosum, lcsh:Science, Multidisciplinary, medicine.diagnostic_test, Cognitive Neurology, 05 social sciences, Neuropsychology, Magnetoencephalography, Middle Aged, Neurology, Auditory Perception, Medicine, Biomedical Imaging, Mental health, Female, Psychology, Research Article, Adult, Adolescent, General Science & Technology, Cognitive Neuroscience, Alpha (ethology), Neuroimaging, Basic Behavioral and Social Science, 050105 experimental psychology, Temporal lobe, 03 medical and health sciences, Developmental Neuroscience, Clinical Research, Behavioral and Social Science, medicine, Humans, Speech, 0501 psychology and cognitive sciences, Biology, lcsh:R, Neurosciences, medicine.disease, Brain Disorders, lcsh:Q, Agenesis of Corpus Callosum, Beta Rhythm, Neuroscience, 030217 neurology & neurosurgery, Executive dysfunction
Abstract

The corpus callosum is hypothesized to play a fundamental role in integrating information and mediating complex behaviors. Here, we demonstrate that lack of normal callosal development can lead to deficits in functional connectivity that are related to impairments in specific cognitive domains. We examined resting-state functional connectivity in individuals with agenesis of the corpus callosum (AgCC) and matched controls using magnetoencephalographic imaging (MEG-I) of coherence in the alpha (8–12 Hz), beta (12–30 Hz) and gamma (30–55 Hz) bands. Global connectivity (GC) was defined as synchronization between a region and the rest of the brain. In AgCC individuals, alpha band GC was significantly reduced in the dorsolateral pre-frontal (DLPFC), posterior parietal (PPC) and parieto-occipital cortices (PO). No significant differences in GC were seen in either the beta or gamma bands. We also explored the hypothesis that, in AgCC, this regional reduction in functional connectivity is explained primarily by a specific reduction in interhemispheric connectivity. However, our data suggest that reduced connectivity in these regions is driven by faulty coupling in both inter- and intrahemispheric connectivity. We also assessed whether the degree of connectivity correlated with behavioral performance, focusing on cognitive measures known to be impaired in AgCC individuals. Neuropsychological measures of verbal processing speed were significantly correlated with resting-state functional connectivity of the left medial and superior temporal lobe in AgCC participants. Connectivity of DLPFC correlated strongly with performance on the Tower of London in the AgCC cohort. These findings indicate that the abnormal callosal development produces salient but selective (alpha band only) resting-state functional connectivity disruptions that correlate with cognitive impairment. Understanding the relationship between impoverished functional connectivity and cognition is a key step in identifying the neural mechanisms of language and executive dysfunction in common neurodevelopmental and psychiatric disorders where disruptions of callosal development are consistently identified.

Published
2012

20. Dual-Mode Modulation of Smad Signaling by Smad-Interacting Protein Sip1 Is Required for Myelination in the Central Nervous System

Author

Elliott H. Sherr, Polina Bukshpun, Ying Chen, Steven G. Kernie, Q. Richard Lu, Qinjie Weng, Veronique van den Berghe, Danny Huylebroeck, Bo Yang, Weinian Shou, Haibo Wang, Yan（陈雁） Chen, Yujiro Higashi, Qiaojun He, Xiaomei Xu, and Eve Seuntjens

Subjects
Central Nervous System, Models, Molecular, Receptor, Platelet-Derived Growth Factor alpha, Cellular differentiation, Oligodendrocyte Transcription Factor 2, Organogenesis, Smad Proteins, SMAD, Myelin, Mice, 0302 clinical medicine, Basic Helix-Loop-Helix Transcription Factors, Cells, Cultured, Myelin Sheath, Oligonucleotide Array Sequence Analysis, Mice, Knockout, 0303 health sciences, Caspase 3, General Neuroscience, 030305 genetics & heredity, Wnt signaling pathway, Age Factors, Gene Expression Regulation, Developmental, Cell Differentiation, Cell biology, Oligodendroglia, medicine.anatomical_structure, Receptor-Interacting Protein Serine-Threonine Kinases, Bone Morphogenetic Proteins, Microcephaly, Signal Transduction, Neuroscience(all), Green Fluorescent Proteins, Nerve Tissue Proteins, Biology, Bone morphogenetic protein, Transfection, Article, Smad7 Protein, OLIG2, 03 medical and health sciences, Microscopy, Electron, Transmission, Intellectual Disability, medicine, Animals, Humans, Immunoprecipitation, Hirschsprung Disease, RNA, Messenger, Zinc Finger E-box Binding Homeobox 2, 030304 developmental biology, Homeodomain Proteins, Gene Expression Profiling, Oligodendrocyte differentiation, Facies, Optic Nerve, Embryo, Mammalian, Molecular biology, Repressor Proteins, Ki-67 Antigen, Animals, Newborn, 030217 neurology & neurosurgery
Abstract

Myelination by oligodendrocytes in the central nervous system (CNS) is essential for proper brain function, yet the molecular determinants that control this process remain poorly understood. The basic helix-loop-helix transcription factors Olig1 and Olig2 promote myelination, whereas bone morphogenetic protein (BMP) and Wnt/β-catenin signaling inhibit myelination. Here we show that these opposing regulators of myelination are functionally linked by the Olig1/2 common target Smad-interacting protein-1 (Sip1). We demonstrate that Sip1 is an essential modulator of CNS myelination. Sip1 represses differentiation inhibitory signals by antagonizing BMP receptor-activated Smad activity while activating crucial oligodendrocyte-promoting factors. Importantly, a key Sip1-activated target, Smad7, is required for oligodendrocyte differentiation and partially rescues differentiation defects caused by Sip1 loss. Smad7 promotes myelination by blocking the BMP- and β-catenin-negative regulatory pathways. Thus, our findings reveal that Sip1-mediated antagonism of inhibitory signaling is critical for promoting CNS myelination and point to new mediators for myelin repair. ispartof: Neuron vol:73 issue:4 pages:713-728 ispartof: location:United States status: published

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