Autismo revisada

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AUTISMO 
Maitê Russo 
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Histórico 
Nervous Child, 2, 217–250, 1943. 
Austríaco 
 
Entrou para a universidade em 1913 
 
Obteve seu diploma de Medicina em 1921 
 
Especializou-se em Psiquiatria infantil 
 
Mudou-se para os Estados Unidos em 1924 
“Autistic disturbances of affective contact” 
1886 - 1981 
Leo Kanner 
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Autismo 
 
 
 
 
Deficiência intelectual 
 
Transtorno global do desenvolvimento 
Transtorno invasivo do desenvolvimento 
NOS - Not Otherwise Specified 
Transtorno do espectro autista 
De acordo com DSM–V (2013): 
n Os Transtornos Globais do Desenvolvimento, 
que inc lu íam o Aut ismo, Transtorno 
Desintegrativo da Infância e as Síndromes de 
Asperger e Rett foram absorvidos por um 
único diagnóstico - Transtornos do Espectro 
Autista. 
 
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Definição 
Transtorno do Espectro Autista (ASD) é um transtorno 
complexo do desenvolvimento caracterizado por: 1) déficit na 
comunicação e interação social, 2) atividades, interesses e 
comportamentos restritivos e repetitivos. 
American Psychiatric Association. (2013) Diagnostic and Statistical Manual of Mental Disorders 
(5th ed.) 
Autismo acomete aproximadamente 1% das crianças e é 4 
vezes mais comum em meninos. 
Prevalência 
Centers for Disease Control and Prevention, (2012) 
Causas 
²  Intoxicação química e ambiental; 
² Estresse materno; 
²  Idade dos pais; 
²  Infecções pré-natais (ex. citomegalovírus, rubéola); 
² Deficiência de zinco; 
² Anormalidades na síntese de melatonina; 
 
 
PSYCHIATRY
REVIEW ARTICLE
published: 18 January 2013
doi: 10.3389/fpsyt.2012.00118
Environmental factors in autism
Andreas M. Grabrucker*
WG Molecular Analysis of Synaptopathies, Neurology Department, Neurocenter of Ulm University, Ulm, Germany
Edited by:
Andreas Reif, University of
Wuerzburg, Germany
Reviewed by:
Konrad Prasad, University of
Pittsburgh School of Medicine, USA
Salvatore Carbonetto, McGill
University Health Centre, Canada
*Correspondence:
Andreas M. Grabrucker ,WG
Molecular Analysis of Synaptopathies,
Anatomy and Cell Biology, Ulm
University, Albert-Einstein Allee 11,
Ulm 89081, Germany.
e-mail: andreas.grabrucker@
uni-ulm.de
Autism is a neurodevelopmental disorders characterized by impairments in communication
and social behavior, and by repetitive behaviors. Although genetic factors might be largely
responsible for the occurrence of autism they cannot fully account for all cases and it is
likely that in addition to a certain combination of autism-related genes, specific environ-
mental factors might act as risk factors triggering the development of autism. Thus, the
role of environmental factors in autism is an important area of research and recent data
will be discussed in this review. Interestingly, the results show that many environmental
risk factors are interrelated and their identification and comparison might unveil a common
scheme of alterations on a contextual as well as molecular level. For example, both, dis-
ruption in the immune system and in zinc homeostasis may affect synaptic transmission
in autism. Thus, here, a model is proposed that interconnects the most important and
scientifically recognized environmental factors. Moreover, similarities in how these risk
factors impact synapse function are discussed and a possible influence on an already well
described genetic pathway leading to the development of autism via zinc homeostasis is
proposed.
Keywords: zinc deficiency, immune system, cytokines, ASD, Shank3, melatonin, risk factor
INTRODUCTION
In the last decade, multiple genes have been implicated in autism,
collectively accounting for approximately 15% of cases includ-
ing autism spectrum disorders (ASDs; Abrahams and Geschwind,
2010). In this context, an increasing number of ASDs can be attrib-
uted to rare genetic changes that are either inherited or appear
de novo and further mutations and candidate genes are increas-
ingly identified. Besides a handful of single specific genes that
can be associated with autism, the current theory supports the
idea of a polygenic inheritance, meaning that multiple genes are
likely to be involved that may predispose an individual to develop
autism. Although inherited factors might be largely responsible
for the occurrence of autism, it is equally clear that genetic aber-
rations cannot fully account for all cases of autism. The California
Autism Twins Study (CATS) for example, with 192 identical and
fraternal twin pairs shows a concordance rate of 77% for male
monozygotic twins and 50% for female identical twins. The rates
among fraternal twins were 31% (male) and 36% (female; Hall-
mayer et al., 2011). The concordance rate of 31/36% of fraternal
twins is higher than the observed rate of 3–14%between siblings of
different ages. Thus, in addition to a genetic heritability, common
factors such as the shared prenatal environment might play a role
in the formation of ASD. Moreover, the increasing prevalence of
autism has drawn attention to the potential involvement of toxins
in our environment. Extending the theory of pure genetic causes,
it seems likely that in addition to a certain combination of autism-
related genes, exposure to specific environmental factors might
be necessary to trigger the development of autism in some indi-
viduals. However, environmental risk factors do not solely cover
the exposure to toxins but include all changes other than those
on a DNA – level such as maternal nutrition, infection during
pregnancy, and prematurity as well as parental age at conception.
This review highlights the role of environmental risk factors
in autism in the context of emerging genetic research which sug-
gests that the synapse is an organelle particularly vulnerable to
genetic disruption and possibly disruption by related environ-
mental influences. In particular, recent data suggest that immune
system abnormalities and altered zinc homeostasis may affect
synaptic transmission. Understanding how genetic and environ-
mental risk factors in autism converge at synapses might provide
a valuable starting point for future work towards uncovering the
patho-mechanisms of autism.
Autism is a developmental disorder and most cases are diag-
nosed by the age of three and as early as 14months (Landa,
2008). Nonetheless, autism might be present from birth on rather
than develop within this developmental time window. Thus, pre-
natal environmental factors are of considerable interest for the
development of autism (Table 1).
PRENATAL VIRAL INFECTION
Failures in early fetal brain development have been linked to a
higher risk for autism and attention has been drawn to offspring
exposed to viral or bacterial infections in utero (Arndt et al.,
2005; Libbey et al., 2005; Miller et al., 2005; Patterson, 2009). For
instance, infections that have been associated with autism include
prenatal influenza, rubella, and cytomegalovirus infections (Pardo
et al., 2005). However, the outcome of exposure to a prenatal viral
infection depends on many factors such as maternal immune sta-
tus, susceptibility of thematernal and fetal host, the developmental
stage of the fetus, the amount of virus reaching the fetus, the
route of access and the infecting virus, and strain of virus (Blat-
tner, 1974). Nevertheless, given the variety of viruses and their
pathogenic effects that can be associated with autism, immuno-
logical imbalance in general might be an underlying risk factor for
www.frontiersin.org January 2013 | Volume 3 | Article 118 | 1
² Forte componente genético; 
REVIEW ARTICLE
Autism Spectrum Disorders and Autistic Traits:
A Decade of New Twin Studies
Angelica Ronald1* and Rosa A. Hoekstra2
1Centre for Brain and Cognitive Development, Department of Psychological Sciences, Birkbeck, Universityof London, London, UK
2Department of Life Sciences, Faculty of Science, The Open University, Milton Keynes, UK
Received 6 July 2010; Accepted 30 November 2010
Researchers continue to pursue a better understanding of the
symptoms, comorbidities, and causes of autism spectrum dis-
orders. In this article we review more than 30 twin studies of
autism spectrum disorders (ASDs) and autistic traits published
in the last decade that have contributed to this endeavor. These
twin studies have reported on theheritability of autism spectrum
disorders and autistic traits in different populations and using
different measurement and age groups. These studies have also
stimulateddebate andnewhypotheses regardingwhyASDsshow
substantial symptom heterogeneity, and what causes their co-
morbidity with intellectual disability, language delay, and other
psychiatric disorders such as ADHD. These studies also reveal
that the etiology of autism and autistic traits assessed in the
general population is more similar than different, which con-
tributes to the question of where the boundary lies between
autism and typical development. Recent findings regarding
molecular genetic and environmental causes of autism are dis-
cussed in the relation to these twin studies. Lastly, methodologi-
cal assumptions of the twin design are given consideration, as
well as issues of measurement. Future research directions are
suggested to ensure that this decade is as productive as the last
in attempting to disentangle the causes of autism spectrum
disorders. ! 2011 Wiley-Liss, Inc.
Key words: autism; twins; genetics; comorbidity
INTRODUCTION
Four twin studies of autistic disorder between 1977 and the late
1990s revolutionized the way we understand autism: by demon-
strating that autism is highly heritable, findings from twin studies
hushed the ‘‘nurture’’ proponents (at the time, this included those
who thought a ‘‘cold’’ style of parenting caused autism [Bettelheim,
1967]), and heralded the start of a multi-million dollar genetics
research area. In the last decade, over 30 twin studies of autism
spectrum disorders and dimensional assessments of autistic traits
have been published.
In this review, we describe how the well-documented original
twin studies of narrowly defined autism have been succeeded by
twin studies of autism spectrum disorders (ASD; the broader
category of conditions that includes autistic disorder as well as
Asperger syndrome and Pervasive developmental disorder not
otherwise specified; PDDNOS), and by a new wave of twin studies
exploring the etiology of dimensional assessments of autistic traits
in the general population. We discuss how this literature contrib-
utes to our understanding of the dimensional nature of autistic
behaviors and how findings from twin studies relate to specific
genetic and environmental causes ofASDandautistic traits. It is not
within the scope of this review to include a systematic account of
molecular genetic findings in ASD; the reader is directed elsewhere
[Abrahams and Geschwind, 2008; Freitag et al., 2010]. Further-
more, we consider how twin research has provided evidence for
etiological heterogeneity in autistic symptoms, and what it has
added to our understanding of the overlap between autism with
intellectual disability, language development and other psychiatric
conditions. Finally, after considering the limitations, assumptions
andmeasurement considerations inherent in these twin studies, we
provide suggestions for future research directions.
THE HERITABILITY OF AUTISM, AUTISM SPECTRUM
DISORDERS, THE BROADER AUTISM PHENOTYPE
It is well-established that twin studies of narrowly defined autism
reported monozygotic (MZ) twin pairs to be more similar than
dizygotic (DZ) twins in their concordance for autism [Folstein and
Grant sponsor: The Netherlands Organization for Scientific Research
(NWO Rubicon).
*Correspondence to:
Dr. Angelica Ronald, Ph.D., Centre for Brain and Cognitive Development,
Department of Psychological Sciences, Birkbeck, University of London,
Malet Street, London WC1E 7XH, UK. E-mail: a.ronald@bbk.ac.uk
Published online 13 January 2011 in Wiley Online Library
(wileyonlinelibrary.com)
DOI 10.1002/ajmg.b.31159
How to Cite this Article:
Ronald A, Hoekstra RA. 2011. Autism
Spectrum Disorders and Autistic Traits:
A Decade of New Twin Studies.
Am J Med Genet Part B 156:255–274.
! 2011 Wiley-Liss, Inc. 255
Neuropsychiatric Genetics
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Diagnóstico 
 
n O diagnóstico de autismo não é tarefa muito 
simples, já que não é muito conhecido pela 
maioria dos médicos e não existem exames 
específicos para detectá-lo. 
Características do autismo 
n Dificuldade na interação social (em geral 
preferem o isolamento e engajam-se em 
atividades individuais); 
n  Dificuldades em expressar emoções; 
n Dificuldade na compreensão de normas sociais; 
n Problemas na comunicação, atraso ou falta de 
linguagem verbal; 
n Dificuldade em brincadeiras de 
 "faz de conta”; 
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Características do autismo 
n Ecolalia; 
n Apresentam dificuldades para fixar o olhar; 
n Preocupação insistente com partes de objetos, 
em vez do todo; 
n Podem ter aversão ao toque; 
n São hipersensíveis à sons, ao toque e outros 
estímulos sensoriais (sobrecarga sensorial); 
n Dificuldade de compreeender o objetivo das 
coisas; 
n padrões de pensamento lógico/técnico extensivo; 
 
Características do autismo 
n Padrões restritos e repetitivos 
de comportamento, interesses 
e atividades; 
n Assume de forma inflexível 
rotinas ou rituais; 
n Estereotipias motoras (se balançar, sacudir 
as mãos); 
n Baixa sensibilidade a dor; 
n interpretação muito literal da linguagem; 
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Características do autismo 
n Falta de consciência com relação a situações de 
perigo; 
n Distúrbios com o sono; 
n Preferência alimentares restritas; 
n Abruptas mudanças de humor; 
n Não atendem quando são chamados pelo nome; 
n Dificuldade em filtrar informações no ambiente 
(relevantes e irrelevantes); 
n Podem exibir comportamentos agressivos; 
O Que fazer??? Como agir??? 
n Familiarize-se com seu aluno; 
n Busque informação com parentes, terapeutas, 
cuidadores e outros professores sobre 
características, preferências e desagrados; 
n Inicie a aula sempre com atividades que os 
alunos são capazes de compreender e realizar e 
só depois introduza tarefas mais difíceis; 
n Esteja atento ao grau distrator do ambiente. 
Procure arrumar o ambiente de maneira que o 
foco da tarefa seja salientado; 
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n Rea l ize at iv idades que incent ivem a 
coordenação visuo-motora, o processamento 
auditivo e promovam a estimuação tátil e 
cinestésica; 
n Reforço positivo e feedback da realização das 
atividades são fundamentais; 
n Promova o contato visual sempre que possível; 
n Utilize desenho e figuras para auxiliar a 
comunicação (as figuras devem ser objetivas); 
n Crie rotinas de trabalho; 
O Que fazer??? Como agir??? 
n Ajude o aluno a criar predições acerca de 
atividades futuras (use pistas); 
n Realize a atividade e simultaneamente 
descreva-a objetivamente, incentivando o 
desenvolvimento da linguagem; 
n Ao se deparar com um comportamente 
inapropriado, tente identificar o elemento 
causador de tal comportamento; 
n Não force a realização de uma atividade ao ver 
que o aluno oferece grande resistência a 
execução da mesma. 
O Que fazer??? Como agir??? 
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