SEARCH · PubMed Health

Results for “Autism Spectrum Disorder”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources

PubMed2002

A genomewide screen for autism-spectrum disorders: evidence for a major susceptibility locus on chromosome 3q25-27.

To identify genetic loci for autism-spectrum disorders, we have performed a two-stage genomewide scan in 38 Finnish families. The detailed clinical examination of all family members revealed infantile autism, but also Asperger syndrome (AS) and developmental dysphasia, in the same set of families. The most significant evidence for linkage was found on chromosome 3q25-27, with a maximum two-point LOD score of 4.31 (Z(max )(dom)) for D3S3037, using infantile autism and AS as an affection status. Six markers flanking over a 5-cM region on 3q gave Z(max dom) >3, and a maximum parametric multipoint LOD score (MLS) of 4.81 was obtained in the vicinity of D3S3715 and D3S3037. Association, linkage disequilibrium, and haplotype analyses provided some evidence for shared ancestor alleles on this chromosomal region among affected individuals, especially in the regional subisolate. Additional potential susceptibility loci with two-point LOD scores >2 were observed on chromosomes 1q21-22 and 7q. The region on 1q21-22 overlaps with the previously reported candidate region for infantile autism and schizophrenia, whereas the region on chromosome 7q provided evidence for linkage 58 cM distally from the previously described autism susceptibility locus (AUTS1).

Adolescent↗

PubMed2006

Elimination diets in autism spectrum disorders: any wheat amidst the chaff?

The use of complementary or alternative treatment approaches in children with autism spectrum disorders (ASDs) is increasing, and the most popular of such approaches are diets that eliminate either gluten or casein, or both. The popularity of these diets indicates a need for more rigorous research into their efficacy. Owing to significant methodological flaws, the currently available data are inadequate to guide treatment recommendations. The purpose of this review is to examine the available trials of gluten/casein diets in children with ASDs regarding the strength of their findings and also concerning points that may be useful in the design of future studies. Seven trials of these diets in ASD are critically reviewed; 6 of these were uncontrolled trials and 1 used a single-blind design. All reported efficacy in reducing some autism symptoms, and 2 groups of investigators also reported improvement in nonverbal cognition. Design flaws in all of the studies weaken the confidence that can be placed in their findings. Careful double-blind, placebo-controlled studies are needed to evaluate whether actual benefit undergirds the diets' popularity and to provide better guidance to clinicians and caregivers. The literature currently available suggests that diets eliminating both gluten and casein (rather than either alone) should be studied first and that outcome measures should include assessments of nonverbal cognition.

Autistic Disorder↗

PubMedDate not supplied

Neural correlates of face and object recognition in young children with autism spectrum disorder, developmental delay, and typical development.

This study utilized electroencephalographic recordings to examine whether young children with autism spectrum disorder (ASD) have impaired face recognition ability. High-density brain event-related potentials (ERPs) were recorded to photos of the child's mother's face versus an unfamiliar female face and photos of a favorite versus an unfamiliar toy from children with ASD, children with typical development, and children with developmental delay, all 3 to 4 years of age (N = 118). Typically developing children showed ERP amplitude differences in two components, P400 and Nc, to a familiar versus an unfamiliar face, and to a familiar versus an unfamiliar object. In contrast, children with ASD failed to show differences in ERPs to a familiar versus an unfamiliar face, but they did show P400 and Nc amplitude differences to a familiar versus an unfamiliar object. Developmentally delayed children showed significant ERP amplitude differences for the positive slow wave for both faces and objects. These data suggest that autism is associated with face recognition impairment that is manifest early in life.

Autistic Disorder↗

PubMed2001

Proinflammatory and regulatory cytokine production associated with innate and adaptive immune responses in children with autism spectrum disorders and developmental regression.

We determined innate and adaptive immune responses in children with developmental regression and autism spectrum disorders (ASD, N=71), developmentally normal siblings (N=23), and controls (N=17). With lipopolysaccharide (LPS), a stimulant for innate immunity, peripheral blood mononuclear cells (PBMCs) from 59/71 (83.1%) ASD patients produced >2 SD above the control mean (CM) values of TNF-alpha, IL-1beta, and/or IL-6 produced by control PBMCs. ASD PBMCs produced higher levels of proinflammatory/counter-regulatory cytokines without stimuli than controls. With stimulants of phytohemagglutinin (PHA), tetanus, IL-12p70, and IL-18, PBMCs from 47.9% to 60% of ASD patients produced >2 SD above the CM values of TNF-alpha depending on stimulants. Our results indicate excessive innate immune responses in a number of ASD children that may be most evident in TNF-alpha production.

Adaptation, Physiological↗

PubMed2006

Autism spectrum disorder and psychopathy: shared cognitive underpinnings or double hit?

BACKGROUND: We measured psychopathic traits in boys with autism spectrum disorder (ASD) selected for difficult and aggressive behaviour. We asked (i) whether psychopathic tendencies can be measured in ASD independent of the severity of autistic behaviour; (ii) whether individuals with ASD with callous-unemotional (CU) traits differ in their cognitive profile from those without such traits; and (iii) how the cognitive data from this study compare with previous data of youngsters with psychopathic tendencies. METHOD: Twenty-eight ASD boys were rated on psychopathic tendencies, autistic traits and a range of cognitive measures assessing mentalizing ability, executive functions, emotion recognition and ability to make moral-conventional distinction. RESULTS: Our results indicate that psychopathic tendencies are not related to severity of ASD. In addition, such tendencies do not seem to be related to core autistic cognitive deficits, specifically in 'mind-reading' or executive function. Boys with co-occurring ASD and CU tendencies share some behaviours and aspects of cognitive profile with boys who have psychopathic tendencies alone. CONCLUSIONS: Callous/psychopathic acts in a small number of individuals with ASD probably reflect a 'double hit' involving an additional impairment of empathic response to distress cues, which is not part and parcel of ASD itself.

Antisocial Personality Disorder↗

PubMed2004

Conducting genetic epidemiology studies of autism spectrum disorders: issues in matching.

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.

Autistic Disorder↗

PubMed2005

Support for the homeobox transcription factor gene ENGRAILED 2 as an autism spectrum disorder susceptibility locus.

Our previous research involving 167 nuclear families from the Autism Genetic Resource Exchange (AGRE) demonstrated that two intronic SNPs, rs1861972 and rs1861973, in the homeodomain transcription factor gene ENGRAILED 2 (EN2) are significantly associated with autism spectrum disorder (ASD). In this study, significant replication of association for rs1861972 and rs1861973 is reported for two additional data sets: an independent set of 222 AGRE families (rs1861972-rs1861973 haplotype, P=.0016) and a separate sample of 129 National Institutes of Mental Health families (rs1861972-rs1861973 haplotype, P=.0431). Association analysis of the haplotype in the combined sample of both AGRE data sets (389 families) produced a P value of .0000033, whereas combining all three data sets (518 families) produced a P value of .00000035. Population-attributable risk calculations for the associated haplotype, performed using the entire sample of 518 families, determined that the risk allele contributes to as many as 40% of ASD cases in the general population. Linkage disequilibrium (LD) mapping with the use of polymorphisms distributed throughout the gene has shown that only intronic SNPs are in strong LD with rs1861972 and rs1861973. Resequencing and association analysis of all intronic SNPs have identified alleles associated with ASD, which makes them candidates for future functional analysis. Finally, to begin defining the function of EN2 during development, mouse En2 was ectopically expressed in cortical precursors. Fewer En2-transfected cells than controls displayed a differentiated phenotype. Together, these data provide further genetic evidence that EN2 might act as an ASD susceptibility locus, and they suggest that a risk allele that perturbs the spatial/temporal expression of EN2 could significantly alter normal brain development.

Autistic Disorder↗

PubMed2007

Brief report: perception of body posture--what individuals with autism spectrum disorder might be missing.

Autism has been associated with atypical face and configural processing, as indicated by the lack of a face inversion effect (better recognition of upright than inverted faces). We investigated whether such atypical processing was restricted to the face or extended to social information found in body postures. An inversion paradigm compared recognition of upright and inverted faces, body postures, and houses. Typical adults demonstrated inversion effects for both faces and body postures, but adults with autism demonstrated only a face inversion effect. Adults with autism may not have a configural processing deficit per se, but instead may have strategies for recognizing faces not used for body postures. Results have implications for therapies employing training in imitation and body posture perception.

Adult↗

PubMed2006

Autism spectrum disorders in relation to distribution of hazardous air pollutants in the san francisco bay area.

OBJECTIVE: To explore possible associations between autism spectrum disorders (ASD) and environmental exposures, we linked the California autism surveillance system to estimated hazardous air pollutant (HAP) concentrations compiled by the U.S. Environmental Protection Agency. METHODS: Subjects included 284 children with ASD and 657 controls, born in 1994 in the San Francisco Bay area. We assigned exposure level by census tract of birth residence for 19 chemicals we identified as potential neurotoxicants, developmental toxicants, and/or endocrine disruptors from the 1996 HAPs database. Because concentrations of many of these were highly correlated, we combined the chemicals into mechanistic and structural groups, calculating summary index scores. We calculated ASD risk in the upper quartiles of these group scores or individual chemical concentrations compared with below the median, adjusting for demographic factors. RESULTS: The adjusted odds ratios (AORs) were elevated by 50% in the top quartile of chlorinated solvents and heavy metals [95% confidence intervals (CIs) , 1.1-2.1], but not for aromatic solvents. Adjusting for these three groups simultaneously led to decreased risks for the solvents and increased risk for metals (AORs for metals: fourth quartile = 1.7 ; 95% CI, 1.0-3.0 ; third quartile = 1.95 ; 95% CI, 1.2-3.1) . The individual compounds that contributed most to these associations included mercury, cadmium, nickel, trichloroethylene, and vinyl chloride. CONCLUSIONS: Our results suggest a potential association between autism and estimated metal concentrations, and possibly solvents, in ambient air around the birth residence, requiring confirmation and more refined exposure assessment in future studies.

Air Pollutants↗

PubMed2002

Adaptive skills and executive function in autism spectrum disorders.

There is active debate regarding the nature of executive dysfunction in autism. Additionally, investigations have yet to show a relationship between deficits in executive function and the everyday behavioral difficulties that may originate from them. The present study examined the relationship between executive abilities and adaptive behavior in 35 children with Autism Spectrum Disorders, using two parent reports of everyday functioning, the Vineland Adaptive Behavior Scales (VABS) and the Behavior Rating Inventory of Executive Function (BRIEF). Results found several relationships: The Initiate and Working Memory domains were negatively correlated with most domains of adaptive behavior. Also, the Communication and Socialization domains of the VABS were negatively correlated with several areas of executive functioning, suggesting that impairments in executive abilities are strongly associated with the deficits in communication, play and social relationships found in children with autism.

Adaptation, Psychological↗

PubMed2006

Physical activity patterns in youth with autism spectrum disorders.

The purpose of this study was to examine age-related physical activity patterns in youth with autism spectrum disorders (ASD). Thirty youth, aged 10-19 years, were divided into three groups: elementary (n=9), middle (n=9) and high (n=12) school. Participants wore an accelerometer and completed an activity questionnaire for seven consecutive days. The main findings were that (a) elementary youth are more active than the other groups, regardless type of day or time period, and (b) there are no consistent patterns in physical activity of youth with ASD according to day or time period. Findings emphasize that interventions for this population should address increasing extracurricular physical activity options during adolescence.

Adolescent↗

PubMed2002

A comparison study of autism spectrum disorder referrals 1997 and 1989.

A number of overseas studies have indicated an increase in the prevalence of Autism Spectrum Disorder (ASD). In the Australian Capital Territory, information (number, age, sex, final diagnosis) was gathered on all children referred for suspected ASD to Child and Adolescent Mental Health Service during 1997, and the findings were compared with those from a similar study in 1989. It was found that (1) there was a 200% increase in positive diagnoses of ASD in 1997 despite a 0.5% decrease in population, (2) there was a wider age range in the 1997 cohort, (3) there was a 26% increase in milder cases in 1997, and (4) the ratio of boys to girls decreased from 8:1 in 1989 to 3.5:1 in 1997. These findings are compared with those overseas, and questions are raised for further exploration.

Adolescent↗

PubMed2004

Neural correlates of facial affect processing in children and adolescents with autism spectrum disorder.

OBJECTIVE: To examine the neural basis of impairments in interpreting facial emotions in children and adolescents with autism spectrum disorders (ASD). METHOD: Twelve children and adolescents with ASD and 12 typically developing (TD) controls matched faces by emotion and assigned a label to facial expressions while undergoing functional magnetic resonance imaging. RESULTS: Both groups engaged similar neural networks during facial emotion processing, including activity in the fusiform gyrus (FG) and prefrontal cortex. However, between-group analyses in regions of interest revealed that when matching facial expressions, the ASD group showed significantly less activity than the TD group in the FG, but reliably greater activity in the precuneus. During the labeling of facial emotions, no between-group differences were observed at the behavioral or neural level. Furthermore, activity in the amygdala was moderated by task demands in the TD group but not in the ASD group. CONCLUSIONS: These findings suggest that children and adolescents with ASD in part recruit different neural networks and rely on different strategies when processing facial emotions. High-functioning individuals with ASD may be relatively unimpaired in the cognitive assessment of basic emotions, yet still show differences in the automatic processing of facial expressions.

Adolescent↗

PubMed2004

Childhood autism spectrum disorder in the Barwon region: a community based study.

OBJECTIVE: To establish a community database for children with autism spectrum disorder (ASD) to determine prevalence and identify subgroups based on key intellectual, clinical and family parameters. METHODS: Data were collected for children previously diagnosed with an ASD in the Barwon region using parental interview and review of the child's paediatric and psychological records. Preschool diagnoses were typically made by specialist psychologists and school-age diagnoses made by a multidisciplinary team. RESULTS: One hundred and seventy-seven children in the Barwon region were identified as having ASD (82% response rate). The prevalence of ASD was one per 255 children aged two to 17 years. The prevalence increased 10 fold over a 16-year period and this increase was relatively even across all levels of child intellectual functioning. Forty-two percent of children were intellectually disabled (IQ < 70) and performance IQ was significantly higher than verbal IQ but typical block design-comprehension subtest patterns were not common. Nine sibling pair families were identified, 24% were labelled as having attention deficit hyperactivity disorder (ADHD), 6% had epilepsy, and 18.3% were macrocephalic where data were available. Family difficulty was associated with the degree of obsessions/rituals, frequency and intensity of anger/aggression, and ADHD but overall was not associated with the child's intellectual status. CONCLUSIONS: The relatively rapid increase in prevalence is consistent with overseas studies and suggests significant changes in diagnostic criteria, increasing community awareness and the need for support at all levels of intellectual functioning. Increased occurrence in siblings and relatives gives further evidence for a genetic cause.

Adolescent↗

PubMed2004

Screening and identifying children with autism spectrum disorders in the public school system: the development of a model process.

Heightened public awareness of autism and increased prevalence estimates of autism spectrum disorders (ASDs) has generated a sense of urgency within the public school system to identify children with these disorders for targeted intervention. Two multidisciplinary groups of professionals, one each from two separate school districts, were identified and trained to provide diagnostic and consultative services. This paper outlines a model process for school personnel to develop a basic level of training and competence in recognizing and serving students who have an ASD by (1) providing an overview of the legal and clinical issues involved in screening for children with ASD within the school system, (2) defining a school-based professional training process and (3) outlining a school-based ASD screening process.

Autistic Disorder↗

PubMed2006

Role of risperidone in children with autism spectrum disorder.

OBJECTIVE: To review the clinical trials investigating the efficacy and safety of risperidone in the treatment of children with autism spectrum disorder (ASD). DATA SOURCES: Searches of MEDLINE/PubMed (1992-February 2006) were conducted, as well as an extensive manual review of journals, using the key words autism and risperidone. STUDY SELECTION AND DATA EXTRACTION: Only double-blind, placebo-controlled trials were included for review. DATA SYNTHESIS: ASD is the most common of the pervasive developmental disorders. The main characteristics (core symptoms) of autism are impairment in social skills, problems communicating, and stereotypical movements. Behavioral manifestations or maladaptive behaviors include aggression, irritability, hyperactivity, inattention, impulsivity, tantrums, and self-injurious behavior. CONCLUSIONS: Based on the data examined, risperidone appears efficacious and safe for treating certain behavioral aspects of autism including irritability, aggression, hyperactivity, and stereotypy. It does not appear to be as effective for the treatment of the core symptoms of autism.

Antipsychotic Agents↗

PubMed2002

Reelin gene alleles and susceptibility to autism spectrum disorders.

A polymorphic trinucleotide repeat (CGG/GCC) within the human Reelin gene (RELN) was examined as a candidate gene for autism spectrum disorders (ASDs). This gene encodes a large extracellular matrix protein that orchestrates neuronal positioning during corticogenesis. The CGG-repeat within the 5' untranslated region of RELN exon 1 was examined in 126 multiple-incidence families. The number of CGG repeats varied from three to 16 in affected individuals and controls, with no expansion or contraction observed during maternal (n = 291) or paternal (n = 287) transmissions in families with autistic probands. Although the frequencies of the RELN alleles and genotypes in affected children were not different from those in the comparison group, a family-based association test (FBAT) showed that the larger RELN alleles (> or = 11 repeats) were transmitted more often than expected to affected children (S = 43, E(S) = 34.5, P = 0.035); this was particularly the case for the 13-repeat RELN allele (S = 22, E(S) = 16, P = 0.034). Affected sib-pair (ASP) analysis found no evidence of excess sharing of RELN alleles in affected siblings. The impact of genotypes with large alleles (> or = 11 repeats) on the phenotypes in individuals with ASD was analyzed by ANOVA in a subset of the families for which results of the Autism Diagnostic Interview-Revised were available. Children with large RELN alleles did not show any difference in scores for questions related to the core symptoms of autistic disorder, but there was a tendency for children with at least one large RELN allele to have an earlier age at first phrase (chi(2) = 3.538, P = 0.06). Thus, although the case-control and affected sib-pair findings did not support a role for RELN in susceptibility to ASD, the more powerful family-based association study demonstrated that RELN alleles with larger numbers of CGG repeats may play a role in the etiology of some cases of ASD, especially in children without delayed phrase speech.

Autistic Disorder↗

PubMed2003

Inhibitory mechanisms in autism spectrum disorders: typical selective inhibition of location versus facilitated perceptual processing.

BACKGROUND: This study examined the inhibitory control mechanisms of selective attention in autism spectrum disorders. Two issues were engaged: First, we extend previous findings of normal inhibition of distractor identity in autism by examining whether inhibition of spatial location is also spared. The second issue concerns the selectivity of inhibition. In non-clinical participants inhibition is selectively directed to the properties of the distractor that compete for the control of action; we examined whether individuals with autism also show normal selectivity of inhibition. METHOD: A negative priming task was used to examine selective spatial inhibition in participants with autism relative to matched non-clinical controls. RESULTS: We discovered that inhibition of distractor spatial location is within normal limits in autism, as is the ability to selectively direct inhibition to task-relevant stimulus features. In addition, we unexpectedly found that the irrelevant perceptual feature of colour produced a facilitation effect in autism, which has not been observed previously in typical controls. CONCLUSIONS: Evidence of colour facilitation implicates more fluent, but presumably less adaptive, perceptual processes in autism.

Adolescent↗