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Abstract
Autism is a neurodevelopmental disorder of genetic origins, with a heritability of about 90%. Autistic disorder is classed within the broad domain of pervasive developmental disorders (PDD) that also includes Rett syndrome, childhood disintegrative disorder, Asperger syndrome, and PDD not otherwise specified (PDD-NOS). Prevalence estimates suggest a rate of 0.1-0.2% for autism and 0.6% for the range of PDD disorders. There is considerable phenotypic heterogeneity within this class of disorders as well as continued debate regarding their clinical boundaries. Autism is the prototypical PDD, and is characterized by impairments in three core domains: social interaction, language development, and patterns of behavior (restricted and stereotyped). Clinical pattern and severity of impairment vary along these dimensions, and the level of cognitive functioning of individuals with autism spans the entire range, from profound mental retardation to superior intellect. There is no single biological or clinical marker for autism, nor is it expected that a single gene is responsible for its expression; as many as 15+ genes may be involved. However, environmental influences are also important, as concordance in monozygotic twins is less than 100% and the phenotypic expression of the disorder varies widely, even within monozygotic twins. Multiple susceptibility factors are being explored using varied methodologies, including genome-wide linkage studies, and family- and case-control candidate gene association studies. This paper reviews what is currently known about the genetic and environmental risk factors, neuropathology, and psychopharmacology of autism. Discussion of genetic factors focuses on the findings from linkage and association studies, the results of which have implicated the involvement of nearly every chromosome in the human genome. However, the most consistently replicated linkage findings have been on chromosome 7q, 2q, and 15q. The positive associations from candidate gene studies are largely unreplicated, with the possible exceptions of the GABRB3 and serotonin transporter genes. No single region of the brain or pathophysiological mechanism has yet been identified as being associated with autism. Postmortem findings, animal models, and neuroimaging studies have focused on the cerebellum, frontal cortex, hippocampus, and especially the amygdala. The cerebello-thalamo-cortical circuit may also be influential in autism. There is evidence that overall brain size is increased in some individuals with autism. Presently there are no drugs that produce major improvements in the core social or pragmatic language deficits in autism, although several have limited effects on associated behavioral features. The application of new techniques in autism research is being proposed, including the investigation of abnormal regulation of gene expression, proteomics, and the use of MRI and postmortem analysis of the brain.
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Affiliation(s)
- Susan L Santangelo
- Psychiatric & Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA.
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102
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Szatmari P, Zwaigenbaum L, Bryson S. Conducting genetic epidemiology studies of autism spectrum disorders: issues in matching. J Autism Dev Disord 2004; 34:49-57. [PMID: 15098957 DOI: 10.1023/b:jadd.0000018074.74369.cd] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The objective of this review is to clarify the role of matching in family genetic studies of autism as a way of defining endophenotypes for linkage analysis. The concept of a confounding variable is reviewed and the importance of considering these in family studies of three endophenotypes in autism are considered: cognitive/language impairments, psychiatric disorders, and autistic-like traits. The importance of matching in infant sibling studies of autism is also addressed. Matching as a way of dealing with confounding variables has an important impact on understanding the extent to which these phenotypes are associated with the genes that confer susceptibility to autism and to the early detection of the disorder. Matching continues to be an important issue in the planning and conduct of family-genetic studies of the autism spectrum disorders, particularly as the search for autism susceptibility genes enters the next generation of studies.
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Affiliation(s)
- Peter Szatmari
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada.
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103
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Abstract
Autism is a complex, behaviorally defined, static disorder of the immature brain that is of great concern to the practicing pediatrician because of an astonishing 556% reported increase in pediatric prevalence between 1991 and 1997, to a prevalence higher than that of spina bifida, cancer, or Down syndrome. This jump is probably attributable to heightened awareness and changing diagnostic criteria rather than to new environmental influences. Autism is not a disease but a syndrome with multiple nongenetic and genetic causes. By autism (the autistic spectrum disorders [ASDs]), we mean the wide spectrum of developmental disorders characterized by impairments in 3 behavioral domains: 1) social interaction; 2) language, communication, and imaginative play; and 3) range of interests and activities. Autism corresponds in this article to pervasive developmental disorder (PDD) of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition and International Classification of Diseases, Tenth Revision. Except for Rett syndrome--attributable in most affected individuals to mutations of the methyl-CpG-binding protein 2 (MeCP2) gene--the other PDD subtypes (autistic disorder, Asperger disorder, disintegrative disorder, and PDD Not Otherwise Specified [PDD-NOS]) are not linked to any particular genetic or nongenetic cause. Review of 2 major textbooks on autism and of papers published between 1961 and 2003 yields convincing evidence for multiple interacting genetic factors as the main causative determinants of autism. Epidemiologic studies indicate that environmental factors such as toxic exposures, teratogens, perinatal insults, and prenatal infections such as rubella and cytomegalovirus account for few cases. These studies fail to confirm that immunizations with the measles-mumps-rubella vaccine are responsible for the surge in autism. Epilepsy, the medical condition most highly associated with autism, has equally complex genetic/nongenetic (but mostly unknown) causes. Autism is frequent in tuberous sclerosis complex and fragile X syndrome, but these 2 disorders account for but a small minority of cases. Currently, diagnosable medical conditions, cytogenetic abnormalities, and single-gene defects (eg, tuberous sclerosis complex, fragile X syndrome, and other rare diseases) together account for <10% of cases. There is convincing evidence that "idiopathic" autism is a heritable disorder. Epidemiologic studies report an ASD prevalence of approximately 3 to 6/1000, with a male to female ratio of 3:1. This skewed ratio remains unexplained: despite the contribution of a few well characterized X-linked disorders, male-to-male transmission in a number of families rules out X-linkage as the prevailing mode of inheritance. The recurrence rate in siblings of affected children is approximately 2% to 8%, much higher than the prevalence rate in the general population but much lower than in single-gene diseases. Twin studies reported 60% concordance for classic autism in monozygotic (MZ) twins versus 0 in dizygotic (DZ) twins, the higher MZ concordance attesting to genetic inheritance as the predominant causative agent. Reevaluation for a broader autistic phenotype that included communication and social disorders increased concordance remarkably from 60% to 92% in MZ twins and from 0% to 10% in DZ pairs. This suggests that interactions between multiple genes cause "idiopathic" autism but that epigenetic factors and exposure to environmental modifiers may contribute to variable expression of autism-related traits. The identity and number of genes involved remain unknown. The wide phenotypic variability of the ASDs likely reflects the interaction of multiple genes within an individual's genome and the existence of distinct genes and gene combinations among those affected. There are 3 main approaches to identifying genetic loci, chromosomal regions likely to contain relevant genes: 1) whole genome screens, searching for linkage of autism to shared genetic markers in populations of multiplex families (families with >1 affected family member; 2) cytogenetic studies that may guide molecular studies by pointing to relevant inherited or de novo chromosomal abnormalities in affected individuals and their families; and 3) evaluation of candidate genes known to affect brain development in these significantly linked regions or, alternatively, linkage of candidate genes selected a priori because of their presumptive contribution to the pathogenesis of autism. Data from whole-genome screens in multiplex families suggest interactions of at least 10 genes in the causation of autism. Thus far, a putative speech and language region at 7q31-q33 seems most strongly linked to autism, with linkages to multiple other loci under investigation. Cytogenetic abnormalities at the 15q11-q13 locus are fairly frequent in people with autism, and a "chromosome 15 phenotype" was described in individuals with chromosome 15 duplications. Among other candidate genes are the FOXP2, RAY1/ST7, IMMP2L, and RELN genes at 7q22-q33 and the GABA(A) receptor subunit and UBE3A genes on chromosome 15q11-q13. Variant alleles of the serotonin transporter gene (5-HTT) on 17q11-q12 are more frequent in individuals with autism than in nonautistic populations. In addition, animal models and linkage data from genome screens implicate the oxytocin receptor at 3p25-p26. Most pediatricians will have 1 or more children with this disorder in their practices. They must diagnose ASD expeditiously because early intervention increases its effectiveness. Children with dysmorphic features, congenital anomalies, mental retardation, or family members with developmental disorders are those most likely to benefit from extensive medical testing and genetic consultation. The yield of testing is much less in high-functioning children with a normal appearance and IQ and moderate social and language impairments. Genetic counseling justifies testing, but until autism genes are identified and their functions are understood, prenatal diagnosis will exist only for the rare cases ascribable to single-gene defects or overt chromosomal abnormalities. Parents who wish to have more children must be told of their increased statistical risk. It is crucial for pediatricians to try to involve families with multiple affected members in formal research projects, as family studies are key to unraveling the causes and pathogenesis of autism. Parents need to understand that they and their affected children are the only available sources for identifying and studying the elusive genes responsible for autism. Future clinically useful insights and potential medications depend on identifying these genes and elucidating the influences of their products on brain development and physiology.
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Affiliation(s)
- Rebecca Muhle
- Class of 2004, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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104
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Abstract
Autism spectrum disorders (ASD) represent a heterogeneous group of developmental disorders that present a challenge to geneticists because of their complex etiology and inheritance. This article reviews some of the advances in our understanding of causation in ASD and the role in which molecular genetic investigations have helped in unraveling the mystery of ASD. There have been few postage stamps issued relevant to ASD. Because of the need for early diagnosis and improved recognition, some countries may consider issuing stamps to highlight the importance of ASD to the population and to raise awareness and money for research funding.
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Affiliation(s)
- A E Chudley
- Section of Genetics and Metabolism, Department of Pediatrics and Child Health, Children's Hospital, University of Manitoba, Winnipeg, Manitoba, Canada.
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105
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Abstract
Autism is a neurologic disorder with impairments in language, social communication, and behavior, which may improve over time, but which persist throughout the lifetime. The evaluation of autism requires a separation of clinical and research objectives and is done best in close cooperation with professionals in the fields of communication, education, and psychology. There are no biologic markers of autism. Regression in language and social communication is present in approximately 30% of children with autism and is most likely to occur between 18 and 24 months of age. Early deficits in social communication can be identified by the assessment of joint attention, affective reciprocity, and metacognition. Current evidence suggests that deficits in social cognition and communication in autism may be related to dysfunction in the amygdala, hippocampus, and related limbic and cortical structures. Other neuroanatomic structures, such as the cerebellum, also may form part of a distributed neuronal network responsible for social cognition and communication. Genetics play a major role in autism, but what is inherited and how broad the inheritable phenotype is remain unclear. At a neurochemical level, the principal neurotransmitter implicated in autism is serotonin. Seizures and epileptiform discharges are common in autism and are linked to cognitive dysfunction. The role of medication is to target specific symptoms and open windows of opportunity that allow implementation of a multimodal individualized educational plan.
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Affiliation(s)
- Roberto Tuchman
- Dan Marino Center, Department of Neurology, Miami Children's Hospital, 2900 South Commerce Parkway, Weston, FL 33331, USA.
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106
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Nicolson R, Szatmari P. Genetic and neurodevelopmental influences in autistic disorder. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2003; 48:526-37. [PMID: 14574828 DOI: 10.1177/070674370304800804] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE In the past, autism was considered to be largely psychogenic. However, research in the last 2 decades indicates that autism is largely caused by genetic factors that lead to abnormal brain development. This article reviews research into the genetic and neurodevelopmental factors underlying autism. METHODS We review the findings from genetic and brain-imaging studies of autism over the past 15 years and synthesize these findings as a guide for future research. RESULTS Genome scans and association studies have suggested potential genomic regions and genes, respectively, that may be involved in the etiology of autism, and there have been some replications of these results. Similarly, the findings that brain volume is exaggerated in autism and corpus callosum size is reduced have also been independently replicated. Unfortunately, studies of other subcortical structures remain inconclusive or contradictory. CONCLUSIONS Overwhelming evidence now supports a neurobiological basis for autism. However, further refinements will be needed to guide future studies, particularly to identify the most informative phenotypes to investigate. Additionally, studies examining the role of genetic factors in the brain abnormalities underlying autism will likely lead to further findings that will enhance our understanding of autism's causes.
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Affiliation(s)
- Rob Nicolson
- Department of Psychiatry, University of Western Ontario, London, Ontario.
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107
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David RB, David CH, Riley LS. Asperger’s and Related Disorders. Pract Neurol 2003. [DOI: 10.1046/j.1474-7766.2003.04144.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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108
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Abstract
Autism is a complex neurodevelopmental disorder characterized by impairment in social interaction accompanied by a delay or lack of language, restricted interests, stereotyped behavior, and repetitive movement. Genetic predisposition to autism is evident from family and twin studies, and heritability in idiopathic autism is estimated at over 90%. Frequency of the disorder is approximately 1:2000 with a male to female ratio of 4:1. Affected individuals look normal at birth, and the symptoms manifest at the first 2-3 years of life. The spectrum of clinical symptoms and the severity of the disorder are variable even among siblings. Family studies and several genome-wide linkage analyses support the hypothesis of complex inheritance with involvement of as many as 10-100 genes of moderate effect. Identification of genes responsible for the phenotype would help to understand the molecular mechanisms of the disorder. Several genes have been proposed to play a role in susceptibility to autism, and this paper will overview those genes and their potential role in the disorder.
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Affiliation(s)
- Irina N Bespalova
- Seaver Autism Research Center, Laboratory of Molecular Neuropsychiatry, Department of Psychiatry, Mount Sinai School of Medicine, New York, NY 10029, USA.
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109
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110
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Hallmayer J, Glasson EJ, Bower C, Petterson B, Croen L, Grether J, Risch N. On the twin risk in autism. Am J Hum Genet 2002; 71:941-6. [PMID: 12297988 PMCID: PMC378547 DOI: 10.1086/342990] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2002] [Accepted: 07/17/2002] [Indexed: 11/03/2022] Open
Abstract
Autism is considered by many to be the most strongly genetically influenced multifactorial childhood psychiatric disorder. In the absence of any known gene or genes, the main support for this is derived from family and twin studies. Two recent studies (Greenberg et al. 2001; Betancur et al. 2002) suggested that the twinning process itself is an important risk factor in the development of autism. If true, this would have major consequences for the interpretation of twin studies. Both studies compared the number of affected twin pairs among affected sib pairs to expected values in two separate samples of multiplex families and reported a substantial and significant excess of twin pairs. Using data from our epidemiological study in Western Australia, we investigated the possibility of an increased rate of autism in twins. All children born between 1980 and 1995 with autism, Asperger syndrome, or pervasive developmental disorder not otherwise specified (PDD-NOS) were ascertained. Of the 465 children with a diagnosis, 14 were twin births (rate 30.0/1,000) compared to 9,640 children of multiple births out of a total of 386,637 births in Western Australia between 1980 and 1995 (twin rate weighted to number of children with autism or PDD per year 26.3/1,000). These data clearly do not support twinning as a substantial risk factor in the etiology of autism. We demonstrate that the high proportion of twins found in affected-sib-pair studies can be adequately explained by the high ratio of concordance rates in monozygotic (MZ) twins versus siblings and the distribution of family size in the population studied. Our results are in agreement with those of two similar studies by Croen et al. (2002) in California and Hultman et al. (2002) in Sweden.
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Affiliation(s)
- Joachim Hallmayer
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, CA, 94304, USA.
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111
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Silverman JM, Smith CJ, Schmeidler J, Hollander E, Lawlor BA, Fitzgerald M, Buxbaum JD, Delaney K, Galvin P. Symptom domains in autism and related conditions: evidence for familiality. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 114:64-73. [PMID: 11840508 DOI: 10.1002/ajmg.10048] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Heterogeneity in autism impairs efforts to localize and identify the genes underlying this disorder. As autism comprises severe but variable deficits and traits in three symptom domains (social interaction, communication, and repetitive behaviors) and shows variability in the presence and emergence of useful phrase speech, different genetic factors may be associated with each. The affected cases (n=457) in multiply affected siblingships (n=212), including a proband with autism and one or more siblings with either autism or marked deficits in autism symptom domains, were assessed using the Autism Diagnostic Interview, Revised. Symptom domain scores and language features were examined to determine their similarity within siblingships. The variance within siblingships was reduced for the repetitive behavior domain and for delays in and the presence of useful phrase speech. These features and the nonverbal communication subdomain provided evidence of familiality when we considered only the diagnosis of autism to define multiply affected siblingships (cases: n=289; siblingships: n=136). In addition, the same familial features identified also appeared familial for those with autism-related conditions. Finally, the level of severity of almost all of the familial features varied within multiplex siblingships independently. The features identified as familial replicate the combined set suggested in earlier, smaller studies. Furthermore, the familiality of these features extend to related conditions of milder severity than autism and appear to be independent. Making distinctions among families by the severity of these features may be useful for identifying more genetically homogeneous subgroups in studies targeted at genes for specific autism-related symptom domains.
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Affiliation(s)
- Jeremy M Silverman
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029, USA.
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112
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Jamain S, Betancur C, Quach H, Philippe A, Fellous M, Giros B, Gillberg C, Leboyer M, Bourgeron T. Linkage and association of the glutamate receptor 6 gene with autism. Mol Psychiatry 2002; 7:302-10. [PMID: 11920157 PMCID: PMC2547854 DOI: 10.1038/sj.mp.4000979] [Citation(s) in RCA: 233] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2001] [Accepted: 08/08/2001] [Indexed: 11/09/2022]
Abstract
A genome scan was previously performed and pointed to chromosome 6q21 as a candidate region for autism. This region contains the glutamate receptor 6 (GluR6 or GRIK2) gene, a functional candidate for the syndrome. Glutamate is the principal excitatory neurotransmitter in the brain and is directly involved in cognitive functions such as memory and learning. We used two different approaches, the affected sib-pair (ASP) method and the transmission disequilibrium test (TDT), to investigate the linkage and association between GluR6 and autism. The ASP method, conducted with additional markers on the 51 original families and in eight new sibling pairs, showed a significant excess of allele sharing, generating an elevated multipoint maximum LOD score (ASPEX MLS = 3.28). TDT analysis, performed in the ASP families and in an independent data set of 107 parent-offspring trios, indicated a significant maternal transmission disequilibrium (TDTall P = 0.0004). Furthermore, TDT analysis (with only one affected proband per family) showed significant association between GluR6 and autism (TDT association P = 0.008). In contrast to maternal transmission, paternal transmission of GluR6 alleles was as expected in the absence of linkage, suggesting a maternal effect such as imprinting. Mutation screening was performed in 33 affected individuals, revealing several nucleotide polymorphisms (SNPs), including one amino acid change (M867I) in a highly conserved domain of the intracytoplasmic C-terminal region of the protein. This change is found in 8% of the autistic subjects and in 4% of the control population and seems to be more maternally transmitted than expected to autistic males (P = 0.007). Taken together, these data suggest that GluR6 is in linkage disequilibrium with autism.
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Affiliation(s)
- Stéphane Jamain
- Génomique fonctionnelle et développement
INSERM : EPI0021Institut Pasteur de ParisUnité d'Immunogénétique humaine,
25 rue du Docteur Roux
75724 Paris Cedex 15,FR
| | - Catalina Betancur
- Neurobiologie et Psychiatrie
INSERM : U513Université Paris XII Val de MarneFaculte de Medecine PARIS XII
8, Rue du General Sarrail
94010 CRETEIL CEDEX,FR
| | - Hélène Quach
- Génomique fonctionnelle et développement
INSERM : EPI0021Institut Pasteur de ParisUnité d'Immunogénétique humaine,
25 rue du Docteur Roux
75724 Paris Cedex 15,FR
| | - Anne Philippe
- Neurobiologie et Psychiatrie
INSERM : U513Université Paris XII Val de MarneFaculte de Medecine PARIS XII
8, Rue du General Sarrail
94010 CRETEIL CEDEX,FR
| | - Marc Fellous
- Génomique fonctionnelle et développement
INSERM : EPI0021Institut Pasteur de ParisUnité d'Immunogénétique humaine,
25 rue du Docteur Roux
75724 Paris Cedex 15,FR
| | - Bruno Giros
- Neurobiologie et Psychiatrie
INSERM : U513Université Paris XII Val de MarneFaculte de Medecine PARIS XII
8, Rue du General Sarrail
94010 CRETEIL CEDEX,FR
| | | | - Marion Leboyer
- Neurobiologie et Psychiatrie
INSERM : U513Université Paris XII Val de MarneFaculte de Medecine PARIS XII
8, Rue du General Sarrail
94010 CRETEIL CEDEX,FR
- Département de Psychiatrie
AP-HPHôpital Albert Chenevier40 rue de Mesly
94000 Créteil,FR
| | - Thomas Bourgeron
- Génomique fonctionnelle et développement
INSERM : EPI0021Institut Pasteur de ParisUnité d'Immunogénétique humaine,
25 rue du Docteur Roux
75724 Paris Cedex 15,FR
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113
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Krebs MO, Betancur C, Leroy S, Bourdel MC, Gillberg C, Leboyer M. Absence of association between a polymorphic GGC repeat in the 5' untranslated region of the reelin gene and autism. Mol Psychiatry 2002; 7:801-4. [PMID: 12192627 PMCID: PMC1913931 DOI: 10.1038/sj.mp.4001071] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2001] [Accepted: 12/21/2001] [Indexed: 11/09/2022]
Abstract
Autism is a complex neurodevelopmental disorder with severe cognitive and communication disabilities, that has a strong genetic predisposition. Reelin, a protein involved in neuronal migration during development, is encoded by a gene located on 7q22, within the candidate region on 7q showing increased allele sharing in previous genome scans. A case/control and family-based association study recently reported a positive association between a trinucleotide repeat polymorphism (GGC) located in the 5' untranslated region (UTR) of the reelin gene and autism. We performed a transmission disequilibrium test (TDT) analysis of the 5'UTR polymorphism in 167 families including 218 affected subjects (117 trios and 50 affected sib pairs) and found no evidence of linkage/association. Our results do not support previous findings and suggest that this GGC polymorphism of the reelin gene is unlikely to be a major susceptibility factor in autism and/or genetic heterogeneity.
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Affiliation(s)
- Marie-Odile Krebs
- Physiopathologie des maladies psychiatriques, développement et vulnérabilité
INSERM : EPI0117Université Paris V René DescartesHôpital Saint-Anne, Bat 78
7, rue Cabanis
75014 Paris,FR
- * Correspondence should be adressed to: Marie-Odile Krebs
| | - Catalina Betancur
- Neurobiologie et Psychiatrie
INSERM : U513Université Paris XII Val de MarneFaculte de Medecine PARIS XII
8, Rue du General Sarrail
94010 Créteil Cedex,FR
| | - Sophie Leroy
- Physiopathologie des maladies psychiatriques, développement et vulnérabilité
INSERM : EPI0117Université Paris V René DescartesHôpital Saint-Anne, Bat 78
7, rue Cabanis
75014 Paris,FR
| | - Marie-Chantal Bourdel
- Physiopathologie des maladies psychiatriques, développement et vulnérabilité
INSERM : EPI0117Université Paris V René DescartesHôpital Saint-Anne, Bat 78
7, rue Cabanis
75014 Paris,FR
| | | | - Marion Leboyer
- Neurobiologie et Psychiatrie
INSERM : U513Université Paris XII Val de MarneFaculte de Medecine PARIS XII
8, Rue du General Sarrail
94010 Créteil Cedex,FR
- Département de Psychiatrie
AP-HP Hôpital Albert Chenevier Hôpital Henri Mondor40 rue de Mesly
94000 Créteil,FR
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114
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Geschwind DH, Sowinski J, Lord C, Iversen P, Shestack J, Jones P, Ducat L, Spence SJ. The autism genetic resource exchange: a resource for the study of autism and related neuropsychiatric conditions. Am J Hum Genet 2001; 69:463-6. [PMID: 11452364 PMCID: PMC1235320 DOI: 10.1086/321292] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Daniel H. Geschwind
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Janice Sowinski
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Catherine Lord
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Portia Iversen
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Jonathan Shestack
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Patrick Jones
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Lee Ducat
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
| | - Sarah J. Spence
- Program in Neurogenetics, Department of Neurology, and Center for Neurobehavioral Genetics, UCLA School of Medicine, and Cure Autism Now Foundation, Los Angeles; Human Biological Data Interchange, Philadelphia; Department of Psychiatry, University of Chicago, Chicago
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Tager-Flusberg H, Joseph R, Folstein S. Current directions in research on autism. MENTAL RETARDATION AND DEVELOPMENTAL DISABILITIES RESEARCH REVIEWS 2001; 7:21-9. [PMID: 11241879 DOI: 10.1002/1098-2779(200102)7:1<21::aid-mrdd1004>3.0.co;2-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
One of the most active areas of current research in the field of developmental disorders is autism. Since the NIH State of the Science conference, held in 1995 (Bristol et al. [1996] J. Autism Dev. Disorders 26:121-154), funding opportunities for comprehensive research programs addressing genetic, neurobiological, and behavioral aspects of this complex disorder have grown exponentially. Although we are far from having a complete understanding of the causes and deficits that define autism, significant progress has been made over the past few years. In this review, we summarize recent developments across a number of different areas of research in the field of autism, including diagnosis; defining the phenotypic features in individuals with autism; genetic bases; and neurobiological deficits.
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Affiliation(s)
- H Tager-Flusberg
- Eunice Kennedy Shriver Center, Waltham, Massachusetts 02452, USA.
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117
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118
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Comi AM, Zimmerman AW, Frye VH, Law PA, Peeden JN. Familial clustering of autoimmune disorders and evaluation of medical risk factors in autism. J Child Neurol 1999; 14:388-94. [PMID: 10385847 DOI: 10.1177/088307389901400608] [Citation(s) in RCA: 256] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Autism is an age-dependent neurologic disorder that is often associated with autoimmune disorders in the patients' relatives. To evaluate the frequency of autoimmune disorders, as well as various prenatal and postnatal events in autism, we surveyed the families of 61 autistic patients and 46 healthy controls using questionnaires. The mean number of autoimmune disorders was greater in families with autism; 46% had two or more members with autoimmune disorders. As the number of family members with autoimmune disorders increased from one to three, the risk of autism was greater, with an odds ratio that increased from 1.9 to 5.5, respectively. In mothers and first-degree relatives of autistic children, there were more autoimmune disorders (16% and 21%) as compared to controls (2% and 4%), with odds ratios of 8.8 and 6.0, respectively. The most common autoimmune disorders in both groups were type 1 diabetes, adult rheumatoid arthritis, hypothyroidism, and systemic lupus erythematosus. Forty-six percent of the autism group reported having relatives with rheumatoid diseases, as compared to 26% of the controls. Prenatal maternal urinary tract, upper respiratory, and vaginal infections; asphyxia; prematurity, and seizures were more common in the autistic group, although the differences were not significant. Thirty-nine percent of the controls, but only 11% of the autistic, group, reported allergies. An increased number of autoimmune disorders suggests that in some families with autism, immune dysfunction could interact with various environmental factors to play a role in autism pathogenesis.
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Affiliation(s)
- A M Comi
- Johns Hopkins Hospital, Division of Pediatric Neurology, Baltimore, MD 21212, USA.
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119
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Burger FL, Lang CM. Diagnoses commonly missed in childhood. Long-term outcome and implications for treatment. Psychiatr Clin North Am 1998; 21:927-40, viii. [PMID: 9890131 DOI: 10.1016/s0193-953x(05)70050-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Psychiatric and developmental disorders with onset in early childhood are often missed and commonly overlooked by adult psychiatrists. These disorders have important continuities into adulthood and are powerful predictors of chronicity, comorbidity, and severity. It is essential that they are recognized and taken into account in the assessment and treatment of the adult patient.
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Affiliation(s)
- F L Burger
- Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, USA
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120
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Szatmari P, Jones MB, Zwaigenbaum L, MacLean JE. Genetics of autism: overview and new directions. J Autism Dev Disord 1998; 28:351-68. [PMID: 9813773 DOI: 10.1023/a:1026096203946] [Citation(s) in RCA: 180] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Genetic epidemiology is the study of inherited factors involved in the etiology of a disease or disorder and uses the methods of both medical genetics and clinical epidemiology. In general, genetic epidemiology tries to answer the following four questions: Is the disorder inherited; What phenotype is inherited; How is it inherited or what is the mode of transmission; and What is the nature of the genetic mutation, if any, that gives rise to the disorder? The hope is that by identifying the gene or genes involved in pathophysiology, a much better understanding of the steps from gene product to phenotype will be possible, leading to improvements in diagnosis, an opportunity for thoughtful family planning, and perhaps, most important, to the development of treatments based on an understanding of the biochemistry of the disorder. We review the current knowledge of the genetic epidemiology of autism and the other pervasive developmental disorders (PDDs) and highlight promising new directions. There seems to be widespread agreement that the PDDs are caused, at least in part, by genetic factors. There is also some agreement on the phenotypic boundaries associated with these same genetic factors. However, many points of uncertainty remain, and several methodologic issues need to be resolved before further progress in mapping susceptibility genes is possible. We do not specifically review molecular studies, medical conditions associated with autism, or the broader autism phenotype, as these topics are covered in other papers in this special issue.
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Affiliation(s)
- P Szatmari
- McMaster University Medical Centre, Hamilton, Ontario, Canada
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121
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Abstract
Recent research has yielded increasing support for neurobiologic theories of autism. A number of family and twin studies support the role of genetics and have led to wide acceptance of autism as an organically based disorder. Controversy persists, however, over the role of congenital medical conditions in the etiology of autism. Two rather divergent views have emerged. One, advocated by Gillberg and colleagues, proposes that up to 30% of cases of autism are associated with a known medical condition. On the other hand, research by Rutter and colleagues suggests the incidence may be closer to 10%. In this retrospective study records on 211 subjects with autism and other developmental disorders are reviewed to determine the prevalence of associated medical conditions and its variability related to the system used to diagnose autism. Results suggest the prevalence of medical conditions with suspected etiologic relationship with autism varies between 10 and 15%, depending on the diagnostic system employed. Further variability in prevalence rates results from a less strict definition of "medical condition" and yields rates between 25 and 37%. Disparate findings in previous research may stem from variability in both diagnostic system employed and which medical conditions are considered significant in the etiology of autism.
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Affiliation(s)
- M Barton
- Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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122
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Abstract
This study compares parents of two autistic children with parents of a Down syndrome (DS) proband, on tests of intelligence, reading and spelling, and executive function. Autism parents performed significantly worse than DS parents on performance IQ, a test of executive function, and some reading measures (e.g. passage comprehension and rapid automatized naming). These results suggest that cognitive deficits may be an expression of the underlying genetic liability for autism and that these characteristics may contribute to a more broadly defined autism phenotype.
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Affiliation(s)
- J Piven
- University of Iowa College of Medicine, Iowa City, USA
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123
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Affiliation(s)
- I Rapin
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, N.Y. 10461, USA
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124
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Hérault J, Petit E, Martineau J, Cherpi C, Perrot A, Barthélémy C, Lelord G, Müh JP. Serotonin and autism: biochemical and molecular biology features. Psychiatry Res 1996; 65:33-43. [PMID: 8953659 DOI: 10.1016/0165-1781(96)02882-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Whole blood and urinary levels of serotonin (5-hydroxytryptamine; 5-HT) and the derivative urinary 5-hydroxyindoleacetic acid (5-HIAA) were measured in normal and autistic subjects. An association was tested between autism and a marker coding for the 5-HT2A serotonergic receptor gene. Significant group (high urinary 5-HT and low whole blood 5-HT in autism) and age effects (urinary 5-HT decrease with age) were found. Moreover, whole blood 5-HT levels were correlated with clinical state. No differences in allele and genotype frequencies for the 5-HT2A receptor marker were found in this autistic population compared with age-matched healthy students.
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Affiliation(s)
- J Hérault
- Laboratoire de Biochimie et de Biologie Moléculaire, INSERM U 316, CHRU Bretonneau, Tours, France
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125
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Petit E, Hérault J, Raynaud M, Cherpi C, Perrot A, Barthélémy C, Lelord G, Müh JP. X chromosome and infantile autism. Biol Psychiatry 1996; 40:457-64. [PMID: 8879465 DOI: 10.1016/0006-3223(96)85270-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Family studies and epidemiologic data in autism show the involvement of genetic factors in the etiology of this syndrome. The frequent association of X chromosome with mental retardation and behavior disturbances raises the question of its implication in the etiology of autism. Several markers of X chromosome were tested in autistic and control populations by association study. The autistic population was submitted to an extensive clinical examination. For the DXS287 marker, chi 2 analysis showed a different allele distribution between control and patient groups. This difference was enhanced when children with the most severe autistic behaviors and the least serious cognitive disorders were selected for statistical comparison. To our knowledge, this is the first association study described using markers of X chromosome in infantile autism. These preliminary results encourage our research on this chromosome, which could be considered as a significant genetic component of the multifactorial etiology of autism.
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Affiliation(s)
- E Petit
- Laboratoire de Biochimie et de Biologie Moléculaire, CHU Bretonneau, Tours, France
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126
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Abstract
To assess head circumference in children with autism, 148 charts were retrospectively reviewed. All of the children met the Diagnostic and Statistical Manual of Mental Disorders (DSM-III or DSM-III-R) criteria for autism and had no known underlying condition that might affect head circumference. In addition, data were collected regarding height, weight, brain imaging, cognitive development, adaptive behavior, and language. The children were divided into two groups: those with head circumference at or above the 98th percentile (Group 1) and those with head circumference below the 98th percentile (Group 2). Group 1 consisted of 27 (18.2%) of the children. Height measurements were significantly higher in Group 1 as compared with Group 2 (P = .0006) as were weight measurements (P = .0003). Group 1 had a significantly lower percentage of females (P = .04) and lower adaptive behavior scores (P = .0067) than Group 2. Routine brain imaging studies could not explain the macrocephaly in Group 1. The etiology of large head circumference and increased growth indices in children with autism is unclear.
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Affiliation(s)
- M Davidovitch
- University Affiliated Cincinnati Center for Developmental Disorders, Children's Hospital Medical Center, OH 45229-3039, USA
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127
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Cryan E, Byrne M, O'Donovan A, O'Callaghan E. A case-control study of obstetric complications and later autistic disorder. J Autism Dev Disord 1996; 26:453-60. [PMID: 8863095 DOI: 10.1007/bf02172829] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The precise etiology of autism remains unclear. Obstetric adversity has been described as one factor that may increase the risk for the disorder. We examined the contemporaneous birth records of 49 children satisfying DSM-III-R criteria for autistic disorder, at four Dublin maternity hospitals, using the previous same-sex live birth in that hospital as a control. Data were evaluated blind to subject status using two obstetric complication (OC) rating scales. No significant differences in obstetric adversity were found between index and control groups. Autistic individuals did not differ from controls in terms of previously described risk factors for this disorder (maternal age, maternal parity, birth order, and low birth weight) in autism. These data do not support the view that OCs increase the risk for later autism.
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Affiliation(s)
- E Cryan
- Department of Child Psychiatry, Cluain Mhuire Family Centre, Blackrock, County Dublin, Ireland
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128
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Szatmari P, Jones MB, Holden J, Bryson S, Mahoney W, Tuff L, MacLean J, White B, Bartolucci G, Schutz C, Robinson P, Hoult L. High phenotypic correlations among siblings with autism and pervasive developmental disorders. AMERICAN JOURNAL OF MEDICAL GENETICS 1996; 67:354-60. [PMID: 8837702 DOI: 10.1002/(sici)1096-8628(19960726)67:4<354::aid-ajmg7>3.0.co;2-m] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The objective of this study was to examine familial factors influencing clinical variation in sibships that contained at least 2 children affected with autism or another form of pervasive developmental disorder (PDD). The sample included a total of 60 families, 23 with multiple cases of PDD and 37 with a single affected child. Measurements of IQ, adaptive behaviors in socialization and communication, and autistic symptoms were taken on all affected children. A high intraclass correlation, especially on IQ and an index of social behaviors, was observed between affected children from the same family. In contrast, low correlations were observed on measurements of IQ and adaptive behavior between affected and unaffected children from the same family. These data indicate that variation in severity of PDD is influenced by familial, and probably genetic, mechanisms. The results are discussed in relation to current theories on the genetics of autism and the heritable mechanisms underlying variations in clinical severity.
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Affiliation(s)
- P Szatmari
- Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada
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129
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Piven J, Arndt S, Bailey J, Andreasen N. Regional brain enlargement in autism: a magnetic resonance imaging study. J Am Acad Child Adolesc Psychiatry 1996; 35:530-6. [PMID: 8919716 DOI: 10.1097/00004583-199604000-00020] [Citation(s) in RCA: 234] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine whether increased brain volume in autism, suggested in previous studies, is the result of general or regional brain size differences and to study the effect of gender on brain size and pattern of enlargement. METHOD Total brain volume and cerebral cortical lobe volumes were examined in 35 autistic and 36 comparison subjects using magnetic resonance imaging and an automated method of brain volume measurement. RESULTS After controlling for height and nonverbal IQ, the authors detected a significant diagnosis x gender effect (F = 7.4; p = .009) for total brain volume. A repeated-measures analysis of variance indicated that the pattern of enlargement (brain region x diagnosis) in autistic subjects differed from that in controls (F = 4.88; p = .0004). Subsequent sex-specific analysis revealed significantly increased total brain volume in autistic males but not females. Analysis of lobe sizes showed significant enlargement in autistic subjects in temporal, parietal, and occipital, but not frontal lobes. CONCLUSIONS These results suggest that brain size is increased in autism and that differences are not generalized but appear to be the result of a pattern of enlargement with increases in the size of specific cortical lobes.
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Affiliation(s)
- J Piven
- Department of Psychiatry, University of Iowa College of Medicine, Iowa City 52242-1057, USA
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130
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Abstract
The neurological, neurochemical, and neurotransmitter level differences as well as genetic influences associated with autism have been studied extensively in the last two decades. The varied findings from research offer hope for better understanding, effective treatment, and, perhaps, cure of this pervasive developmental disorder.
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Affiliation(s)
- J B Murray
- Department of Psychology, St. John's University, Jamaica, NY 11439, USA
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131
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Hallmayer J, Spiker D, Lotspeich L, McMahon WM, Petersen PB, Nicholas P, Pingree C, Ciaranello RD. Male-to-male transmission in extended pedigrees with multiple cases of autism. AMERICAN JOURNAL OF MEDICAL GENETICS 1996; 67:13-8. [PMID: 8678108 DOI: 10.1002/(sici)1096-8628(19960216)67:1<13::aid-ajmg2>3.0.co;2-t] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Despite strong genetic influences in autism, the true mode of inheritance remains unknown. Sex differences in autism have been described in both singleton and multiplex families [Lord et al., 1982; Volkmar et al., 1993; McLennan et al., 1993; Lord, 1992]: Boys outnumber girls by 3 or 4 to 1, and so a sex-linked mode of transmission must also be considered. The key characteristic of X-linkage is that all sons of affected men are unaffected (no male-to-male transmission). In the present study, which is part of an ongoing linkage project in autism, we describe 77 multiplex autism families, 11 of who are affected cousin or half-sibling families. By using these families, it is possible to trace the path of genetic transmission and observe whether the hypothesis of X-linkage is tenable. Of 11 extended pedigrees from 77 multiplex families, six show male-to-male transmission; in these families, X-linkage can be excluded as the genetic basis for their autism. The data from the other five families are compatible with either an autosomal or an X-linked mode of transmission. The key point to emerge, then, is that autism cannot be exclusively an X-linked disorder; there must be an autosomal mode of transmission at least in some families. Thus we must consider the alternative hypotheses that autism is either entirely autosomal, or it is genetically heterogeneous, involving at least one autosomal locus with genderspecific expression, as well as a possible locus on the X-chromosome.
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Affiliation(s)
- J Hallmayer
- Nancy Pritzker Laboratory of Developmental and Molecular Neurobiology, California, USA
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132
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Szatmari P, Jones MB, Fisman S, Tuff L, Bartolucci G, Mahoney WJ, Bryson SE. Parents and collateral relatives of children with pervasive developmental disorders: a family history study. AMERICAN JOURNAL OF MEDICAL GENETICS 1995; 60:282-9. [PMID: 7485262 DOI: 10.1002/ajmg.1320600405] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The objective of this study was to see whether, using the family history method, the risk for pervasive developmental disorder (PDD), cognitive impairments, and other psychiatric symptoms is greater in the parents and collateral relatives of probands with PDD compared to a control group. A semistructured family history interview was carried out with the parents of 52 probands with PDD and 33 parents of controls. Rates of cognitive impairments and psychiatric problems were not found more frequently in parents or relatives of PDD probands compared to relatives of controls, but four cases of PDD were reported among the extended families of the PDD probands. The relatives with PDD were related to the probands through the maternal line, possibly suggesting some form of maternal influence on inheritance or reduced penetrance in females with the PDD genotype.
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Affiliation(s)
- P Szatmari
- Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada
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133
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Petit E, Hérault J, Martineau J, Perrot A, Barthélémy C, Hameury L, Sauvage D, Lelord G, Müh JP. Association study with two markers of a human homeogene in infantile autism. J Med Genet 1995; 32:269-74. [PMID: 7643354 PMCID: PMC1050373 DOI: 10.1136/jmg.32.4.269] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Epidemiological data and family studies in autism show that there is a genetic susceptibility factor in the aetiology of this syndrome. We carried out an association study in infantile autism. Two markers of the homeogene EN2 involved in cerebellar development were tested in a population of 100 autistic children and in a population of 100 control children. With the MP4 probe showing a PvuII polymorphism, significant differences in the allele frequencies between the two populations were found (chi 2 = 7.99, df = 1, p < 0.01). With the MP5 probe showing an SstI polymorphism, no difference appeared (chi 2 = 1.17, not significant). Several clinical examinations allowed us to characterise the autistic children. Most of them had high scores for autistic behaviour and language disorders but low scores for neurological syndromes. Two children had a significant family history and six children had confirmed syndromes or diseases of genetic origin. Discriminant analysis between clinical and molecular data did not give significant results. These preliminary results must be supported by further analyses of this gene and by studies of its potential involvement in the pathophysiology of the autistic syndrome.
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Affiliation(s)
- E Petit
- INSERM U316, CHU Bretonneau, Tours, France
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134
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Leboyer M, Plumet M, Goldblum M, Perez‐Diaz F, Marchaland C. Verbal versus visuospatial abilities in relatives of autistic females. Dev Neuropsychol 1995. [DOI: 10.1080/87565649509540609] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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135
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Martineau J, Hérault J, Petit E, Guérin P, Hameury L, Perrot A, Mallet J, Sauvage D, Lelord G, Müh JP. Catecholaminergic metabolism and autism. Dev Med Child Neurol 1994; 36:688-97. [PMID: 7914177 DOI: 10.1111/j.1469-8749.1994.tb11911.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The authors determined levels of dopamine (DA) and its derivatives homovanillic acid (HVA), 3-4 dihydroxyphenylacetic acid (DOPAC), 3 methoxytyramine and norepinephrine + epinephrine (NE + E) in the urine, and DA, E and NE in the whole blood of 50 autistic children aged between 1 year 11 months and 16 years. An association was tested for between markers coding for the enzymes and D3 dopaminergic receptor genes implicated in the monoaminergic pathway and autism, using restriction fragment-length polymorphism. There were significant modifications of catecholamine metabolites, but no difference for allele frequencies of the genes coding for tyrosine hydroxylase, dopamine beta hydroxylase and DRD3 in this population compared with a healthy school population matched for chronological age. However, some of the data encourage a more complete study of chromosome 11.
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Affiliation(s)
- J Martineau
- INSERUM U316, Département de Neurophysiologie et de Psychopathologie du développement, CHU Bretonneau, Tours, France
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136
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Grewe TS, Danhauer JL, Danhauer KJ, Thornton AR. Clinical use of otoacoustic emissions in children with autism. Int J Pediatr Otorhinolaryngol 1994; 30:123-32. [PMID: 8063498 DOI: 10.1016/0165-5876(94)90195-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Transient-evoked otoacoustic emissions (TEOAEs) may offer an objective way of evaluating the peripheral auditory systems of difficult-to-test patients. Children with autism are often suspected of hearing loss, but frequently will not respond on traditional behavior auditory tests. The clinical feasibility of obtaining TEOAEs on children with autism was evaluated here. The use of TEOAEs for 6 children (12 ears) with autism is described here regarding the acquisition of data, the presence of emissions, and their amplitudes and reproducibility. Emissions were recorded for 9 of the 12 ears; the lack of emissions for the remaining 3 ears was due to lack of patient cooperation. The results suggest that TEOAEs may be a valuable part of the audiologic test battery for children with autistic behavior. The ease of obtaining emissions for these children with autism is discussed.
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Affiliation(s)
- T S Grewe
- Department of Speech and Hearing Sciences, University of California, Santa Barbara 93106
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137
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Piven J, Wzorek M, Landa R, Lainhart J, Bolton P, Chase GA, Folstein S. Personality characteristics of the parents of autistic individuals. Psychol Med 1994; 24:783-795. [PMID: 7991760 DOI: 10.1017/s0033291700027938] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Personality characteristics of 87 parents of autistic probands and 38 parents of Down's syndrome probands were examined using a standardized personality interview. Using best-estimate ratings derived from subject and informant interviews, parents of autistic individuals were rated significantly higher than controls on three characteristics: aloof, untactful and undemonstrative. When ratings were based on interviews with subjects only, parents of autistic probands were rated as significantly more aloof, untactful and unresponsive. There were no significant differences between parent groups on ratings based on informant interviews only. The implications of these findings for future family studies of autism are discussed.
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Affiliation(s)
- J Piven
- Johns Hopkins University, School of Medicine, Department of Psychiatry, Baltimore, Maryland
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138
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Bolton P, Macdonald H, Pickles A, Rios P, Goode S, Crowson M, Bailey A, Rutter M. A case-control family history study of autism. J Child Psychol Psychiatry 1994; 35:877-900. [PMID: 7962246 DOI: 10.1111/j.1469-7610.1994.tb02300.x] [Citation(s) in RCA: 627] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Family history data on 99 autistic and 36 Down's syndrome probands are reported. They confirmed a raised familial loading for both autism and more broadly defined pervasive developmental disorders in siblings (2.9% and 2.9%, respectively, vs 0% in the Down's group) and also evidence for the familial aggregation of a lesser variant of autism, comprising more subtle communication/social impairments or stereotypic behaviours, but not mental retardation alone. Between 12.4 and 20.4% of the autism siblings and 1.6% and 3.2% of the Down's siblings exhibited this lesser variant, depending on the stringency of its definition. Amongst autistic probands with speech, various features of their disorder (increased number of autistic symptoms; reduced verbal and performance ability) as well as a history of obstetric complications, indexed an elevation in familial loading. No such association was seen in the probands without speech, even though familial loading for the lesser variant in this subgroup, was significantly higher than in the Down's controls. The findings suggest that the autism phenotype extends beyond autism as traditionally diagnosed; that aetiology involves several genes; that autism is genetically heterogeneous; and that obstetric abnormalities in autistic subjects may derive from abnormality in the foetus.
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Affiliation(s)
- P Bolton
- M.R.C. Child Psychiatry Unit, Institute of Psychiatry, London, U.K
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139
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Spiker D, Lotspeich L, Kraemer HC, Hallmayer J, McMahon W, Petersen PB, Nicholas P, Pingree C, Wiese-Slater S, Chiotti C. Genetics of autism: characteristics of affected and unaffected children from 37 multiplex families. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 54:27-35. [PMID: 8178836 DOI: 10.1002/ajmg.1320540107] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Evidence from twin and family studies strongly suggests that genetic factors play a prominent role in the etiology of some cases of infantile autism. Genetic factors would be expected to be especially strong in families with multiple autistic members (multiplex families). This report describes the identification and evaluation of 44 families with two or more autistic children collected as part of a genetic linkage study in autism. Families were referred with a presumptive classification of multiplex autism. Children referred as autistic, as well as their presumptively normal siblings, were assessed using the Autism Diagnostic Interview (ADI) and the Autism Diagnostic Observation Scale (ADOS). Thirty-seven of the 44 families (87%) had at least two children who met diagnostic criteria for autism on the ADI. Of the total group of 117 children evaluated in those families, 83 (71%) met all ADI criteria and could be unambiguously classified as autistic (affected), 26 (22%) met none of the ADI criteria and were classified as not autistic (unaffected), and 8 (7%) were classified as uncertain because they met one or more but not all of the ADI cutpoints. Autistic siblings were not significantly concordant for most autism characteristics, for IQ, or for verbal ability. Significant concordances were found, however, for behaviors related to rituals and repetitive play, and for social impairments in the expression and understanding of facial expressions of emotion.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D Spiker
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, CA 94305
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140
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Abstract
Clinical descriptions of 14 adults with mild autism are presented. Structured questionnaires, extensive medical and social histories, and mental status examinations were conducted independently by several clinicians who concurred with the diagnoses of autism. These 14 patients demonstrate (1) that mild forms of autism can remain undiagnosed into adulthood; (2) that developmental histories and patients' reports may not provide evidence of developmental delays and characteristic symptoms during childhood despite their presence at adult mental status examination; (3) that mild previously undetected autism should be considered in the differential diagnoses of perplexing adult patients.
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Affiliation(s)
- E R Ritvo
- Division of Child Psychiatry and Biobehavioral Sciences, UCLA School of Medicine
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141
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Hérault J, Petit E, Buchler M, Martineau J, Cherpi C, Perrot A, Sauvage D, Barthelemy C, Muh JP, Lelord G. Lack of association between three genetic markers of brain growth factors and infantile autism. Biol Psychiatry 1994; 35:281-3. [PMID: 8186333 DOI: 10.1016/0006-3223(94)91260-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- J Hérault
- Department of Biochemistry, INSERM U 316, Tours, France
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142
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Szatmari P, Jones MB, Tuff L, Bartolucci G, Fisman S, Mahoney W. Lack of cognitive impairment in first-degree relatives of children with pervasive developmental disorders. J Am Acad Child Adolesc Psychiatry 1993; 32:1264-73. [PMID: 8282674 DOI: 10.1097/00004583-199311000-00022] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The objective of this study was to test the hypothesis that mild cognitive impairments aggregate in the unaffected first-degree relatives of probands with autism or pervasive developmental disorders (PDD). METHOD The unaffected siblings and parents of 52 PDD probands and 33 Down syndrome and low birth weight controls were administered a battery of psychometric tests. The tests included measures previously found to be depressed in siblings of autistic children as well as cognitive deficits seen in PDD subjects of normal IQ. In addition, the Vineland Adaptive Behavior Scales were administered to siblings to measure the social-communication impairments found in PDD. RESULTS Neither the siblings nor parents of the PDD probands demonstrated lower cognitive or adaptive behavior scores compared with controls. Developmental histories did not reveal greater rates of social, cognitive, or language delays, nor was there evidence to suggest that relatives of subgroups of PDD probands were different from each other. CONCLUSION These findings indicate that, apart from relatives with PDD, cognitive and social impairments do not aggregate in the families of PDD probands.
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Affiliation(s)
- P Szatmari
- Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada
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143
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Abstract
A pair of monozygotic and a pair of dizygotic twins with autism and hypomelanosis of Ito skin-abnormalities are described. These observations are further evidence of the frequent association between these two conditions, already demonstrated in the literature, and suggest a possibly higher incidence of single gene associations among cases of autism with known genetic basis.
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Affiliation(s)
- M Zappella
- Department of Child Neuropsychiatry, USL 30, Siena, Italy
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144
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Mason-Brothers A, Ritvo ER, Freeman BJ, Jorde LB, Pingree CC, McMahon WM, Jenson WR, Petersen PB, Mo A. The UCLA-University of Utah epidemiologic survey of autism: Recurrent infections. Eur Child Adolesc Psychiatry 1993; 2:79-90. [PMID: 29871451 DOI: 10.1007/bf02098863] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two hundred and forty-one children with autism were ascertained and diagnosed (DSM-III criteria) in an epidemiologic survey of Utah. Pediatric and other pertinent medical records were abstracted for 233 patients and 66 of their siblings without autism for otitis media, upper respiratory, and other infections. A significantly greater number of children with autism had recurrent otitis media, upper respiratory and other infections than their nonautistic siblings. A greater number of children with autisru with recurrent infections had lower IQ scores, seizures, hearing deficits, delayed motor milestones, poorer speech, congenital anomalies, feeding problems, vomiting, diarrhea, and other types of infections than children with autism with mild or no infections. The only significant pre-, peri-, or postnatal risk factors between children with autism with recurrent, mild or no infection was an increase in the maternal-fetal incompatibility (ABO or Rh) in the recurrent infection group. Half the families with more than one child with autism had recurrent infections and 72% of those children with concurrent diseases which effect the CNS had recurrent infections. Methodological limitations are discussed.
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Affiliation(s)
| | - Edward R Ritvo
- Neuropsychiatric Institute, 760 Westwood Plaza, 90024, Los Angeles, CA, USA
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145
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146
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147
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Lotspeich LJ, Ciaranello RD. The neurobiology and genetics of infantile autism. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1993; 35:87-129. [PMID: 8463065 DOI: 10.1016/s0074-7742(08)60569-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Autism is a syndrome with multiple etiologies, as is made clear both by the evidence of neurobiological research and by the catalog of disorders that present with autistic behaviors. What remains unclear are the specific neuropathological mechanisms that produce autistic behaviors; for example, is there a common neuroanatomic pathology for all cases of autism, or can autistic behaviors emerge from different pathological sequences within the brain? Although it is premature to generalize, neuropathological studies appear to have identified common abnormalities in the cerebellum and limbic system of at least five autistic subjects. These subjects, with variable levels of mental retardation, demonstrated marked Purkinje cell loss in the cerebellar hemispheres, together with retained fetal neuronal circuitry in cerebellar nuclei and increased neuronal packing in specific regions of the limbic system, amygdala, and hippocampus. The architecture of the cerebral cortex was not affected. Although our knowledge of brain functioning is incomplete, alterations of the kind noted in the cerebellum and limbic system could reasonably produce autistic behaviors. For more detail, readers are directed to a review of cerebellar contributions to higher functions by Schmahmann (1991). Neuroimaging studies allow less resolution of brain structure than do neuroanatomic studies, and the reported findings from neuroimaging are somewhat contradictory. However, a number of investigators have reported structural abnormalities in ventricle size and cerebral hemispheric asymmetry using CT. MRI, which offers greater resolution, has uncovered some consistent findings, along with a variety of nonspecific abnormalities. Common abnormalities include reduced volume of cerebellar hemispheres and vermal lobules--findings not inconsistent with the above-mentioned neuropathological defects. It is also interesting to note that individuals with fragile X syndrome have similar cerebellar findings. PET and NMR studies of autism are at a preliminary stage, but these methodologies allow insight into the functioning of the brain, rather than simply brain anatomy. Recent PET studies indicating decreased association between paired regions of the brains of autistic subjects are of interest, particularly if they can be confirmed and refined by additional studies. Neurophysiological studies also offer insight into brain function, but are subject to numerous methodological criticisms. Nevertheless, recent reports of diminished P300 waves and absent NC components in autistic subjects seem to indicate fundamental defects in attention and secondary processing, which could help explain the self-stimulatory behaviors often seen in autism. The disturbances in brain development associated with autism can be produced in a number of ways, and at different times during development of the nervous system.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- L J Lotspeich
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, California 94305
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148
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Eme RF. Selective Females Affliction in the Developmental Disorders of Childhood: A Literature Review. ACTA ACUST UNITED AC 1992. [DOI: 10.1207/s15374424jccp2104_5] [Citation(s) in RCA: 158] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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149
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Abstract
While there seems to be general agreement that genetic factors play some role in the etiology of autism, many important questions remain unresolved. The purpose of this paper is to review five issues with respect to the association between low IQ and autism from a familial-genetic viewpoint: (1) does IQ estimate the severity of the autistic genotype?; (2) what is the relationship between probands' and sibs' IQs?; (3) what is the relationship between parents' and probands' IQs?; (4) why do females with autism have lower IQs than males with the disorder?; and (5) does IQ vary with the cause of autism? With respect to each issue, possible resolutions are outlined, as are the implications for understanding the genetic mode of transmission. The review concludes with a possible model for the genetic etiology of autism.
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Affiliation(s)
- P Szatmari
- Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada
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150
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Autism: Etiology, differential diagnosis, and behavioral assessment update. JOURNAL OF PSYCHOPATHOLOGY AND BEHAVIORAL ASSESSMENT 1991. [DOI: 10.1007/bf00961426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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