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Allelic heterogeneity at the serotonin transporter locus (SLC6A4) confers susceptibility to autism and rigid-compulsive behaviors.

Autism is a spectrum of neurodevelopmental disorders with a primarily genetic etiology exhibiting deficits in (1) development of language and (2) social relationships and (3) patterns of repetitive, restricted behaviors or interests and resistance to change. Elevated platelet serotonin (5-HT) in 20%-25% of cases and efficacy of selective 5-HT reuptake inhibitors (SSRIs) in treating anxiety, depression, and repetitive behaviors points to the 5-HT transporter (5-HTT; SERT) as a strong candidate gene. Association studies involving the functional insertion/deletion polymorphism in the promoter (5-HTTLPR) and a polymorphism in intron 2 are inconclusive, possibly because of phenotypic heterogeneity. Nonetheless, mounting evidence for genetic linkage of autism to the chromosome 17q11.2 region that harbors the SERT locus (SLC6A4) supports a genetic effect at or near this gene. We confirm recent reports of sex-biased genetic effects in 17q by showing highly significant linkage driven by families with only affected males. Association with common alleles fails to explain observed linkage; therefore, we hypothesized that preferential transmission of multiple alleles does explain it. From 120 families, most contributing to linkage at 17q11.2, we found four coding substitutions at highly conserved positions and 15 other variants in 5' noncoding and other intronic regions transmitted in families exhibiting increased rigid-compulsive behaviors. In the aggregate, these variants show significant linkage to and association with autism. Our data provide strong support for a collection of multiple, often rare, alleles at SLC6A4 as imposing risk of autism.

Alanine↗

Spatial frequency and face processing in children with autism and Asperger syndrome.

Two experiments were designed to investigate possible abnormal face processing strategies in children with autistic spectrum disorders. A group of 11 children with autism was compared to two groups of normally developing children matched on verbal mental age and on chronological age. In the first experiment, participants had to recognize faces on the basis of identity, emotion, gaze direction, gender, and lip reading. All aspects of face processing, except for identity matching, were deficient in the autistic population compared with controls. In the second study, children had to match faces on either high-(i.e., local facial features) or low-spatial frequency information (i.e., global configuration of faces). Contrary to the control subjects, children with autism showed better performance when using high rather than low spatial frequency, confirming face-processing peculiarities in this population.

Adolescent↗

An intervention technique for children with autistic spectrum disorder: joint attentional routines.

Virtually all children with autism are deficient in joint attentional skills. The impact of this deficit may be understood in the context of pragmatically based explanations of language acquisition. In this view, each step in the ontongeny of joint attention is consequential for language development. Thus, it is important that speech-language pathologists understand the developmental course of joint attention so that intervention may start at the earliest step possible. In this article, we review the literature on joint attention and its relationship with other rule systems of language. We discuss the ontogeny of joint attention in typical children. Finally, we describe the developmental course of joint attention as a framework for language intervention through the study of one case.

Attention↗

Pervasive developmental disorders not otherwise specified. A developmental-psychopathological approach for the development of made-to-measure treatment planning.

Diagnosis and classification of autism and related pervasive developmental disorders is both easy and difficult. Infantile autism is a characteristic syndrome on which many publications have appeared in the last 50 years. Conversely, the diagnosis and even the classification of children with pervasive developmental disorders related to autism is difficult. Although children with these disorders are twice as numerous as children with infantile autism, growing attention has been directed to at the latter group since the last decade. In this paper, autism and related disorders are described as a developmental disorder as well as a spectrum disorder. The spectrum of clinical symptoms can be explained, of which infantile autism is the most severe and prototypical manifestation. A working model is presented which accounts for all the problems of children with pervasive developmental disorders. An illustration of working with the model in practice is also given. The main lines of treatment and stages in treatment are briefly described.

Autistic Disorder↗

Prevalence of autism and parentally reported triggers in a north east London population.

BACKGROUND: The recorded prevalence of autistic spectrum disorders has risen over recent decades. Measles, mumps and rubella (MMR) vaccine has been blamed, by causing a "new variant" form of "regressive autism" associated with "autistic enterocolitis". AIMS: To estimate the prevalence of autism and to assess any changes in parental perception regarding the onset or causes of autism. METHODS AND RESULTS: A total of 567 children with autistic spectrum disorder in five districts in north east London were identified, born 1979-98. Reported autism, excluding the 94 cases of Asperger's syndrome, increased by year of birth until 1992, since when prevalence has plateaued. This flattening off persisted after allowing for expected delay in diagnosis in more recent birth cohorts. The age at diagnosis of autistic spectrum disorder was estimated to have decreased per five year period since 1983, by 8.7% for childhood autism and by 11.0% for atypical autism. There was some evidence that MMR was more likely to be mentioned as a trigger after August 1997 than before. CONCLUSIONS: The prevalence of autism, which was apparently rising from 1979 to 1992, reached a plateau from 1992 to 1996 at a rate of some 2.6 per 1000 live births. This levelling off, together with the reducing age at diagnosis, suggests that the earlier recorded rise in prevalence was not a real increase but was likely due to factors such as increased recognition, a greater willingness on the part of educationalists and families to accept the diagnostic label, and better recording systems. The proportion of parents attributing their child's autism to MMR appears to have increased since August 1997.

Adolescent↗

Autism and attachment: a meta-analytic review.

METHOD: Sixteen studies on attachment in children with autism were reviewed, and ten studies with data on observed attachment security (N = 287) were included in a quantitative meta-analysis. RESULTS: Despite the impairments of children with autism in reciprocal social interaction, the majority of the studies found evidence for attachment behaviours in these children. In four samples using the Strange Situation procedure the average percentage of secure attachments amounted to 53% (n = 72). Meta-analytic results showed that children with autism were significantly less securely attached to their parents than comparison children, and the combined effect size for this difference was moderate (r =.24). Children with autism displayed less attachment security than comparisons without autism, but this difference disappeared in samples with children with higher mental development, and in samples in which autism was mixed with less severe symptoms of autistic spectrum disorders. CONCLUSIONS: It is concluded that attachment security is compatible with autism, and can be assessed with Strange Situation type of procedures. The co-morbidity of autism and mental retardation appears to be associated with attachment insecurity.

Autistic Disorder↗

The Autism Genome Project: goals and strategies.

Autism is a complex neurodevelopmental disorder with a broad spectrum of symptoms and varying severity. Currently, no biological diagnosis exists. Although there has been a significant increase in autism genetics research recently, validated susceptibility genes for the most common, sporadic forms of autistic disorder, as well as familial autism, have yet to be identified. The identification of autism-susceptibility genes will not only assist in the identification and/or development of better medications that can help improve the health and neurodevelopment of children with autism, but will also allow for better perinatal diagnosis. The Autism Genome Project (AGP) is a large-scale, collaborative genetics research project initiated by the National Alliance for Autism Research and the National Institutes of Health, and is aimed at sifting through the human genome in search of autism-susceptibility genes. Phase I of the AGP will consist of genome-wide scans utilizing both SNP array and microsatellite technologies. Linkage analysis will subsequently be performed on approximately 1500 pedigrees as will downstream fine-mapping and sequencing of the critical linkage intervals. Ultimately, the vision will be to identify the exact nucleotide variants within genes which give rise to predisposition. The AGP intends to move the field of autism clinical management forward by answering questions about the causal mechanisms underlying the pathophysiology of autism. From this knowledge, therapeutic targets for drug treatments, and ultimately, a newborn screening diagnostic that would allow for early intervention, can begin to be developed.

Autistic Disorder↗

Screening for autism in young children: The Modified Checklist for Autism in Toddlers (M-CHAT) and other measures.

The literature on the importance of early identification and early intervention for children with developmental disabilities such as autism continues to grow. The increased prevalence of autistic spectrum disorders has fostered research efforts on the development and validation of autism-specific screening instruments for use with young children. There are currently several such autism-specific screening tools meant to be used with young children in various stages of development. Data from a few of these screening instruments have been published, and they include the Checklist for Autism in Toddlers (CHAT), Pervasive Developmental Disorders Screening Test (PDDST), Screening Tool for Autism in Two year olds (STAT), Checklist for Autism in Toddlers-23 (CHAT-23), and the Modified Checklist for Autism in Toddlers (M-CHAT). In this review, these five tools designed for use with children under three years old will be highlighted. In particular, the Modified Checklist for Autism in Toddlers (M-CHAT) will be discussed.

Age Factors↗

A founder variant in TBCB is associated with global developmental delay, autism spectrum, and spastic paraparesis.

PURPOSE: Hereditary spastic paraparesis (HSP) is a genetically diverse group of Mendelian disorders characterized by length-dependent axonal degeneration. Microtubule dysfunction is a known mechanism in HSP that impairs axonal dynamics. TBCB encodes tubulin-folding cofactor B (TBCB), which, along with TBCE, regulates αβ-heterodimer dynamics and neuronal axonal growth. Here, we describe a new form of complicated HSP caused by a founder variant in TBCB. METHODS: Exome sequencing revealed a homozygous c.589T>A p.(Tyr197Asn) variant in TBCB in a cohort of 10 individuals assembled through genematching tools. Protein function was assessed using Saccharomyces cerevisiae ortholog ALF1, and a CRISPR-Cas9-generated homologous mutant in Drosophila melanogaster. TBCB expression and localization were examined in fibroblasts using western blot and immunofluorescence. RESULTS: Participants displayed late-childhood-onset spastic paraparesis, global developmental delay, and autism spectrum. TBCB protein levels were reduced in affected fibroblasts. The ALF1 mutant in yeast increased benomyl sensitivity, resembling a loss-of-function phenotype. In Drosophila melanogaster, the homologous mutant led to reduced survival and impaired climbing ability. CONCLUSION: We describe a novel neurodevelopmental disorder with spastic paraparesis and a high carrier rate in the Ashkenazi Jewish population. Our results indicate that TBCB has a vital role in the development of central nervous system and potentially in axonal function in humans.

Humans↗

Autism: developing a strategy for nursing to prevent discrimination.

The final phase of the Disability Discrimination Act (DDA) comes into force in October 2004. The DDA Code of Practice is a document to guide organizations in the implementation of and compliance with the Act. The DDA Code of Practice (2002) makes reference to specific impairments, such as hearing and visual impairments, and there are numerous examples of how 'reasonable adjustments' can be made to enable access to those so disabled. There is recognition that some impairments are hidden, e.g. learning disabilities and diabetes. However, no mention is made of those with autism. The impairments of autism including Asperger syndrome are also 'hidden impairments' as defined by the DDA and this will mean that it will not be immediately obvious as to how the Act will help nurses to amend their practice to enable people with autism full inclusion and access to health care. This article will explore practical implications and outline how nurses can develop their practice to be compliant with the Act and to ensure good 'health care' practice for people diagnosed within the autism spectrum.

Autistic Disorder↗

Fatty acid metabolism in neurodevelopmental disorder: a new perspective on associations between attention-deficit/hyperactivity disorder, dyslexia, dyspraxia and the autistic spectrum.

There is increasing evidence that abnormalities of fatty acid and membrane phospholipid metabolism play a part in a wide range of neurodevelopmental and psychiatric disorders. This proposal is discussed here in relation to attention-deficit/hyperactivity disorder (ADHD), dyslexia, developmental coordination disorder (dyspraxia) and the autistic spectrum. These are among the most common neurodevelopmental disorders of childhood, with significant implications for society as well as for those directly affected. However, controversy still surrounds both the identification and management of these conditions, and while their aetiology is recognized as being complex and multifactorial, little progress has yet been made in elucidating predisposing factors at the biological level. An overview is provided here of the contents of this Special Issue, which contains a selection of reports from a unique multidisciplinary workshop involving both researchers and clinicians. Its purpose was to explore the possibility that ADHD, dyslexia, dyspraxia and autism fall within a phospholipid spectrum of disorders. This proposal could explain the high degree of co-morbidity between these conditions, their aggregation within families and relation to other psychiatric disorders, and a range of associated features that are already well known at a clinical level. The existing evidence for fatty acid abnormalities in these disorders is summarized, and new approaches are outlined that have the potential to improve both the identification and the management of these and related neurodevelopmental and psychiatric conditions.

Attention Deficit Disorder with Hyperactivity↗

Autistic disorder and viral infections.

Autistic disorder (autism) is a behaviorally defined developmental disorder with a wide range of behaviors. Although the etiology of autism is unknown, data suggest that autism results from multiple etiologies with both genetic and environmental contributions, which may explain the spectrum of behaviors seen in this disorder. One proposed etiology for autism is viral infection very early in development. The mechanism, by which viral infection may lead to autism, be it through direct infection of the central nervous system (CNS), through infection elsewhere in the body acting as a trigger for disease in the CNS, through alteration of the immune response of the mother or offspring, or through a combination of these, is not yet known. Animal models in which early viral infection results in behavioral changes later in life include the influenza virus model in pregnant mice and the Borna disease virus model in newborn Lewis rats. Many studies over the years have presented evidence both for and against the association of autism with various viral infections. The best association to date has been made between congenital rubella and autism; however, members of the herpes virus family may also have a role in autism. Recently, controversy has arisen as to the involvement of measles virus and/or the measles, mumps, rubella (MMR) vaccine in the development of autism. Biological assays lend support to the association between measles virus or MMR and autism whereas epidemiologic studies show no association between MMR and autism. Further research is needed to clarify both the mechanisms whereby viral infection early in development may lead to autism and the possible involvement of the MMR vaccine in the development of autism.

Animals↗

Evaluating in-home training for fathers of children with autism using single-subject experimentation and group analysis methods.

BACKGROUND: Autism, or the broader category of autistic spectrum disorder, is a complex developmental disability with uncertain etiologies that appears to be increasing in prevalence. Researchers have stated that training programs for children with autism are most effective when they are individualized, address communicative intent of child behaviors, and promote social reciprocity between children and individuals with whom they have regular contact. Yet, to date, most of what is known comes solely from studying mothers, who have traditionally been the most accessible parent. OBJECTIVES: In this study the mother-child in-home training program was modified and evaluated for its effects on the acquisition of training skills by fathers and on precommunication skills by the autistic children. METHODS: Frequency counts of skills taught to fathers and targeted child behaviors were obtained from videotaped father-child play sessions. These data were analyzed for each father-child dyad by using graphs and visual analyses, which are integral parts of single-participant experimentation. This procedure was replicated across all of the father-child dyads. Data were then grouped and analyzed using the more traditional repeated measures analysis of variance. RESULTS: The most significant findings were increases in father use of imitating with animation (p < .0001) and child initiating following training (p < .0004). Also noteworthy were significant increases in father responding (p < .0005) and child vocalizations (p < .05). DISCUSSION: Results of the study indicate that the in-home training for fathers of children with autism was effective and valued by the participating families.

Adult↗

The effect of coloured overlays on reading ability in children with autism.

Abnormalities of colour perception in children with autistic spectrum disorders have been widely reported anecdotally. However, there is little empirical data linking difficulties in colour perception with academic achievement. The Wilkins Rate of Reading Test was administered with and without Intuitive Coloured Overlays to 19 children with autistic spectrum disorders and to the same number of controls individually matched for age and intelligence. Findings showed that 15 out of 19 (79%) children with autism showed an improvement of at least 5% in reading speed when using a coloured overlay. In contrast only 3 of 19 (16%) control group children showed such an improvement. The findings suggest that coloured overlays may provide a useful support for reading for children with autism.

Achievement↗

Autism in adulthood: the concepts of identity and difference.

It was not until 1980 that autistic spectrum disorders were officially recognized as disorders of development and not of psychoses (Wing, 1996). (In this article the term 'autism' will be used to refer to all individuals diagnosed across the autistic spectrum, including people with Asperger syndrome.) There will be many adults with autism aged over 20 years of age who are not appropriately diagnosed and who are not receiving relevant care (Trevarthen et al, 1998). Many will have been the victims of a medical model of treatment as opposed to receiving the necessary education and support. This article, the second of a two-part series (the first article (Vol 9(12): 779-84) dealt with children with autism) will explore how contemporary knowledge can help healthcare professionals to support adults with autism in the development of positive self-identities.

Adaptation, Psychological↗

In vivo 1H-magnetic resonance spectroscopy study of amygdala-hippocampal and parietal regions in autism.

OBJECTIVE: The neural basis for autistic spectrum disorders is unclear, but abnormalities in the development of limbic areas and of glutamate have been suggested. Proton magnetic resonance spectroscopy ((1)H-MRS) can be used to measure the concentration of brain metabolites. However, the concentration of glutamate/glutamine in brain regions implicated in autistic spectrum disorders has not yet been examined in vivo. METHOD: The authors used (1)H-MRS to investigate the neuronal integrity of the amygdala-hippocampal complex and a parietal control region in adults with autistic spectrum disorders and healthy subjects. RESULTS: People with autistic spectrum disorders had a significantly higher concentration of glutamate/glutamine and creatine/phosphocreatine in the amygdala-hippocampal region but not in the parietal region. CONCLUSIONS: Abnormalities in glutamate/glutamine may partially underpin the pathophysiology of autistic spectrum disorders, and the authors confirm earlier reports that limbic areas are metabolically aberrant in these disorders.

Adult↗

Language disorders in children with autism.

Language development is delayed in most children on the autistic spectrum. The children are dysphasic as well as autistic. Comprehension and pragmatics are invariably affected. Lower level mixed receptive/expressive disorders involve phonological and syntactical processing, whereas higher level processing disorders involve semantics and formulation of discourse. In some children, lower level disorders may be so severe as to preclude speech, whereas in others phonology may be deficient in spontaneous production but not in repetition. Abnormal features of autistic language include aberrant prosody, immediate and delayed echolalia (scripts), and perseveration. Electrophysiological studies indicate that brainstem-evoked potentials are normal. Even in fully verbal individuals with autism, early and late cortical components of auditory, but not visual, event-related potentials are abnormal. Appropriate intervention must address language and behavioral issues. In children with severely defective auditory language, provision of visual language to supplement speech is essential.

Autistic Disorder↗

Immunizations, immunology, and autism.

Public fears of rising rates of children being diagnosed with autistic spectrum disorders has led to a fear that immunizations, specifically the measles-mumps-varicella vaccine (MMR), may trigger autism. This article reviews theories of immunization as a risk factor for autism, including thimerosal exposure. We also review theories of autoimmunity as a predisposing genetic risk in autistic patients. We summarize from multiple population-based studies and extensive review committee reports that neither immunization nor thimerosal exposure has been conclusively linked to autism. Current treatments for autoimmunity in autism are reviewed and summarized as being only anecdotally effective, with no controlled studies to conclusively determine effectiveness. The goal of this article is to allow child neurologists to effectively counsel parents of autistic patients about vaccination risks and treatment options in presumed cases of autoimmune dysfunction.

Autistic Disorder↗