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Results for “Autism Spectrum Disorder”

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PubMed2000

Venlafaxine in children, adolescents, and young adults with autism spectrum disorders: an open retrospective clinical report.

Autism is characterized by social deficits, communication and language impairments, narrow restricted interests, repetitive behaviors, inattention, and hyperactivity. While selective serotonin reuptake inhibitors have demonstrated efficacy in treating core symptoms of autism, norepinephrine reuptake inhibitors have demonstrated efficacy in symptoms of attention-deficit hyperactivity disorder (ADHD). An open, retrospective clinical study with venlafaxine evaluated its effect on core symptoms of autism as well as associated features of ADHD. Ten consecutive subjects meeting Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), criteria for an autism spectrum disorder were treated with venlafaxine, initiated at 12.5 mg per day and adjusted on a flexible basis. Six of 10 completers were judged to be sustained treatment responders, by scoring 1 (very much improved) or 2 (much improved) on the Clinical Global Impressions improvement scale. Venlafaxine was effective in low dosages (mean, 24.37 mg/day; range, 6.25 to 50 mg/day) and was well tolerated. Improvement was noted in repetitive behaviors and restricted interests, social deficits, communication and language function, inattention, and hyperactivity. Controlled treatment trials with venlafaxine are warranted in autism spectrum disorders.

Adult↗

PubMed2000

The development of siblings' understanding of autism spectrum disorders.

While professionals commonly advocate sharing information about autism spectrum disorders with siblings, no guidelines currently exist that describe what types of information might be relevant for siblings at different ages. To address this issue, the interviewing method described by Bibace and Walsh (1979, 1980), which measures cognitive sophistication in thinking about illness, was adapted to examine perspectives on autism spectrum disorders. Sixty-three siblings of individuals with autism or related disorders were interviewed using this measure. Parents were given the same interview as their child, and asked to predict their child's responses. Children's reasoning became more mature with age, but developed at a delayed rate compared to norms for illness concepts. Although accurate in estimating their child's understanding of the definition and cause of their sibling's diagnosis, parents tended to overestimate their child's understanding of the disorder's impact.

Adolescent↗

PubMed2000

Discovery of allelic variants of HOXA1 and HOXB1: genetic susceptibility to autism spectrum disorders.

BACKGROUND: Family studies have demonstrated that the autism spectrum disorders (ASDs) have a major genetic etiologic component, but expression and penetrance of the phenotype are variable. Mice with null mutations of Hoxa1 or Hoxb1, two genes critical to hindbrain development, have phenotypic features frequently observed in autism, but no naturally occurring variants of either gene have been identified in mammals. METHODS: By sequencing regions of genomic DNA of patients with autism spectrum disorders, we detected a substitution variant at HOXA1 and an insertion variant at HOXB1, both in coding regions of the genes. Fifty-seven individuals ascertained for a diagnosis of an ASD, along with 166 of their relatives, were typed for these variants. Two non-ASD populations were typed, and the frequency of the newly identified alleles was determined in all groups. The genotypes of the ASD families were tested for conformation to Hardy-Weinberg proportions and Mendelian expectations for gene transmission. RESULTS: The frequency of the variants was 10-25% in persons of European or African origin. In the ASD families, there was a significant deviation from the HOXA1 genotype ratios expected from Hardy-Weinberg proportions (P = 0.005). Among affected offspring, a significant deviation from Mendelian expectation in gene transmission (P = 0.011) was observed. No statistically significant effects were detected when the same analyses were applied to the HOXB1 locus, but there was evidence of an interaction between HOXA1, HOXB1, and gender in susceptibility to ASDs. CONCLUSIONS: The results support a role for HOXA1 in susceptibility to autism, and add to the existing body of evidence implicating early brain stem injury in the etiology of ASDs.

Abnormalities, Multiple↗

PubMed2006

Epilepsy in autism spectrum disorders.

Epilepsy is quite common in autism spectrum disorders, and it is increasingly recognized as an additional clinical problem that must be dealt with. The rate of comorbidity varies, depending upon the age and type of disorder, and currently the conservative estimate of comorbidity cases is 20-25% of the whole spectrum. Major risk factors for seizure occurrence are mental retardation and additional neurological disorders, as well as some specific associated medical conditions. Autism with regression has been reported in one-third of children with previously normal or nearly normal development. In an unknown proportion of these subjects, epileptic disorders are concomitant, leading to so-called autistic epileptiform regression. Furthermore, epileptiform abnormalities without seizures are frequent in this population and their role in the development of the nuclear disturbances of autism is controversial. The therapeutic approaches to epilepsy in autism are conventional treatments, yet when seizures are not evident, there is still controversy. Anticonvulsant medications could also potentially interfere with mood and behavioral disturbances frequently observed in ASD. The current understanding of the association between epilepsy and autism is still limited, but from a clinical point of view this association should not be overlooked, and it should be routinely investigated.

Adolescent↗

PubMed2000

Treatment of seizure disorders and EEG abnormalities in children with autism spectrum disorders.

The treatment of seizure disorders EEG epileptiform abnormalities without epilepsy in children with autism spectrum disorders (ASD) is considered within the context of the relationship of epilepsy and epileptiform disorders to language, behavior, and cognition. There is an increased prevalence of both epilepsy and abnormal potentially epileptogenic activity in children with ASD. Anecdotal evidence suggests that the use of anticonvulsants to treat epileptiform discharges thought to be producing dysfunction in selected aspects of cognition, language, or behavior makes a positive difference in a subgroup of children with ASD, but there is inadequate evidence on which to base specific recommendations. There is, at present, no scientific justification for considering epilepsy surgery in children with ASD in the absence of intractable clinical seizures.

Anticonvulsants↗

PubMed2006

Attention does not modulate neural responses to social stimuli in autism spectrum disorders.

We investigated whether individuals with autism spectrum disorders (ASD) would show attentional modulation for social (face) and non-social (house) stimuli. Sixteen individuals with ASD and 16 matched control participants completed a task in which pairs of face and house stimuli were present on every trial, with one of the pairs randomly assigned to attended locations and the other to unattended locations. Both mass-univariate (SPM) and region of interest analyses suggested that responses to houses were modulated by attention in both groups, but that only the control participants demonstrated attentional modulation of face-selective regions. Thus, the participants with ASD demonstrated a lack of attentional modulation which was particularly evident for the social stimulus. Analyses of effective connectivity indicated that these results were due to a failure of attention to modulate connectivity between extrastriate areas and V1. We discuss how these results may suggest a mechanism to explain the reduced salience of social stimuli in ASD.

Adult↗

PubMed2004

Autism spectrum disorder: screening, diagnosis, and medical evaluation.

Autism spectrum disorder (ASD) are a group of behaviorally defined neurodevelopmental disabilities with core deficits in socialization, communication, and behavior, although the presentation can be extremely variable. This article describes the core deficits in ASD, as well as the differential diagnosis and the more commonly associated comorbid disorders. The importance of early diagnosis is emphasized, and screening and assessment tools are reviewed. Finally, the role of the pediatric neurologist is discussed with regard to specific components of the evaluation, including history, physical examination, and ancillary testing.

Autistic Disorder↗

PubMed2006

The genetics of autism spectrum disorders.

Epidemiological twin studies demonstrate that autism spectrum disorders (ASDs) represent genetic disorders. Subsequent analyses indicate that the causes of ASDs include less common single-gene mutations and chromosomal abnormalities, as well as ASDs caused by multiple interacting genes of weak effect. Genome-wide linkage analysis has identified several susceptibility loci for the ASDs, and positional and functional candidate genes have been identified that appear to represent susceptibility genes for the ASDs. Analysis of additional larger samples and the use of genome-wide association and high-throughput variant detection will lead to the identification of further genes for ASDs.

Autistic Disorder↗

PubMed2026

Genomic landscape of autism spectrum disorder in Brazil.

Genomic studies of autism spectrum disorder (ASD) have largely excluded admixed populations. To address this gap, we characterized the genomic landscape of ASD in Brazil by combining a systematic literature review with whole-exome sequencing analysis of 441 Brazilian individuals and their families. Our analysis revealed a conclusive molecular diagnosis in 13.1% of probands. The diagnostic yield was higher among individuals with clinical features, particularly comorbid signs of intellectual disability, hypotonia, and seizures, providing a basis for prioritizing genetic testing. The sample presented a diverse ancestry, with major European, African, and Native American contributions. Notably, more than half of the identified rare risk variants were located on non-European haplotypes. Both de novo and inherited variants contributed to ASD risk, and we reinforce NPAS3 as a candidate ASD risk gene. This study provides the first comprehensive genomic overview of ASD in a large Brazilian cohort, reinforcing the critical need to include diversely admixed populations in genomic research to expand the understanding of ASD architecture and improve diagnostic strategies in resource-limited settings.

Journal Article↗

PubMed1996

Autism spectrum disorders in children with physical or mental disability or both. II: Screening aspects.

The Autism Behavior Checklist (ABC) was used as a screening instrument in a study of autism spectrum disorders in a population of children with mental retardation or physical disability or both. The ABC score clearly reflected behavioural problems found in children with mental retardation and not only behaviours typical of autism. If the cut-off score used was 45 (lower than recommended by the original investigators), children with autistic disorder without multiple other disabilities were reliably identified, with an acceptable rate of false positive cases. In order not to miss other autism spectrum disorders, all cases with several omitted items in their checklists were examined in more detail. The Childhood Autism Rating Scale (CARS) distinguished reasonably well between autistic disorder and other autism spectrum disorders.

Adolescent↗

PubMed2022

Profiling Genome-Wide DNA Methylation in Children with Autism Spectrum Disorder and in Children with Fragile X Syndrome.

Autism spectrum disorder (ASD) is an early onset, developmental disorder whose genetic cause is heterogeneous and complex. In total, 70% of ASD cases are due to an unknown etiology. Among the monogenic causes of ASD, fragile X syndrome (FXS) accounts for 2-4% of ASD cases, and 60% of individuals with FXS present with ASD. Epigenetic changes, specifically DNA methylation, which modulates gene expression levels, play a significant role in the pathogenesis of both disorders. Thus, in this study, using the Human Methylation EPIC Bead Chip, we examined the global DNA methylation profiles of biological samples derived from 57 age-matched male participants (2-6 years old), including 23 subjects with ASD, 23 subjects with FXS with ASD (FXSA) and 11 typical developing (TD) children. After controlling for technical variation and white blood cell composition, using the conservatory threshold of the false discovery rate (FDR ≤ 0.05), in the three comparison groups, TD vs. AD, TD vs. FXSA and ASD vs. FXSA, we identified 156, 79 and 3100 differentially methylated sites (DMS), and 14, 13 and 263 differential methylation regions (DMRs). Interestingly, several genes differentially methylated among the three groups were among those listed in the SFARI Gene database, including the PAK2, GTF2I and FOXP1 genes important for brain development. Further, enrichment analyses identified pathways involved in several functions, including synaptic plasticity. Our preliminary study identified a significant role of altered DNA methylation in the pathology of ASD and FXS, suggesting that the characterization of a DNA methylation signature may help to unravel the pathogenicity of FXS and ASD and may help the development of an improved diagnostic classification of children with ASD and FXSA. In addition, it may pave the way for developing therapeutic interventions that could reverse the altered methylome profile in children with neurodevelopmental disorders.

Child↗

PubMed2006

Volumetric analysis and three-dimensional glucose metabolic mapping of the striatum and thalamus in patients with autism spectrum disorders.

OBJECTIVE: In patients with autism, behavioral deficits as well as neuroimaging studies of the anterior cingulate cortex suggest ventral rather than dorsal striatal and thalamic abnormalities in structure and function. The authors used imaging studies to map volumetric and metabolic differences within the entire dorsoventral extent of the striatum and thalamus. METHOD: Magnetic resonance imaging (MRI) and positron emission tomography (PET) were used to measure volumes and metabolic activity in the thalamus, caudate, and putamen in 17 patients with autism or Asperger's disorder and 17 age- and sex-matched comparison subjects. Subjects performed a serial verbal learning test during the [(18)F]-fluorodeoxyglucose uptake period. The regions of interest were outlined on contiguous axial MRI slices. After PET/MRI coregistration, region-of-interest coordinates were applied to the PET scan for each individual. Between-group differences in metabolism were assessed by three-dimensional statistical probability mapping. RESULTS: The patients with autism spectrum disorders had greater volumes of the right caudate nucleus than comparison subjects as well as a reversal of the expected left-greater-than-right hemispheric asymmetry. Patients also had lower relative glucose metabolic rates bilaterally in the ventral caudate, putamen, and thalamus. Patients with autism had lower metabolic activity in the ventral thalamus than those with Asperger's disorder, but they did not differ from comparison subjects in metabolic activity in the caudate nucleus. CONCLUSIONS: These results are consistent with a deficit in the anterior cingulate-ventral striatum-anterior thalamic pathway in patients with autism spectrum disorders. The results also suggest an important role for the caudate in helping support working-memory demands.

Adolescent↗

PubMed1996

Autism spectrum disorders in children with physical or mental disability or both. I: Clinical and epidemiological aspects.

The prevalence of autism spectrum disorders was studied in all children with mental retardation and/or motor disability in a defined geographical region over a two-year follow-up period. In the general population, the prevalence of autistic disorder was 0.09% at the end of the follow-up period -a minimum estimate, as children with average intelligence were not screened. Autism spectrum disorders were found in 19.8% of children with mental retardation, including strictly defined autistic disorder (DSM-III-R criteria) in 8.9%; the two-year follow-up yielded a higher prevalence of 11.7% with autistic disorder. Among children with cerebral palsy, 10.5% had an autism spectrum disorder. Clear co-variation was found between mental retardation, epilepsy and autism spectrum disorders in this population of children with neurodevelopmental disorders.

Adolescent↗

PubMed2006

[Differential diagnosis of psychopathy and autism spectrum disorders in adults. Empathic deficit as a core symptom].

BACKGROUND: There is an overlap between the symptoms of psychopathy and autism spectrum disorders. AIM: To contribute to an adequate differential diagnosis of these disorders. METHOD: We reviewed the literature with the help of PubMed, using as key words: 'empathy', 'psychopathy', 'autism', 'aggression' and 'antisocial' for the period 1980-2004. We also consulted papers listed in the bibliographic references for these articles. RESULTS: Empathic deficit is a core symptom of both disorders. In psychopathy there are signs of an emotional empathic deficit, an inability to feel along with another person (insensitivity). Research into autism spectrum disorders points to a cognitive empathic deficit, an inability to take the perspective of another person (innocence). The antisocial behaviour that can accompany both disorders might be due to the type of empathic deficit. In psychopathy the antisocial behavior often involves insensitive manipulation and exploitation ofanother person. In autism spectrum disorders there is sometimes antisocial behaviour which could be caused partly by incorrect evaluation of social situations. In both psychopathy and autism spectrum disorders dysfunctioning of the orbitoftontal cortex and the amygdala is often mentioned as a possible cause of empathic deficit. CONCLUSION: An accurate diagnosis of the type of empathic deficit involved could help to differentiate psychopathy from autism spectrum disorders. Good diagnostic tools are not yet available.

Asperger Syndrome↗

PubMed2006

Screening for autism spectrum disorders: what is the evidence?

This review examines the evidence for screening for autism spectrum disorders in the general population and the information needed to inform screening policy. The UK National Screening Committee criteria are taken as the framework. These criteria cover the condition, the screening test, the treatment and the screening programme as a whole. With respect to the condition, reasons for variation in prevalence estimates for autism spectrum disorders need to be resolved and there are few longitudinal studies to describe the natural history of autism spectrum disorders that include data on children identified at an early age. There is no screening test suitable for use in a population setting that has been fully validated. There is insufficient evidence regarding the effectiveness of interventions. This review supports the current policy position of the National Screening Committee, that on the basis of existing evidence, screening for autism spectrum disorders cannot be recommended.

Autistic Disorder↗

PubMed2006

Early screening for autism spectrum disorders: update on the modified checklist for autism in toddlers and other measures.

Early intervention for autism spectrum disorders necessitates early detection. This need has led to widespread agreement across disciplines that screening is critical in very young children. Two screening issues are highlighted in this review. Level of screening refers to the type of sample: Level I is defined as an unselected sample, and Level II consists of selected children already identified as being at risk for a developmental disorder. Breadth or scope of screening refers to the range of difficulties the screening tool attempts to identify: broad screening instruments identify multiple range of developmental difficulties, whereas disorder-specific tools focus on a single disorder or class of disorders. Broad developmental instruments reviewed include the Parents' Evaluation of Developmental Status and the Ages and Stages Questionnaires; autism-specific tools reviewed include the Checklist for Autism in Toddlers, the Modified Checklist for Autism in Toddlers (M-CHAT), the Pervasive Developmental Disorders Screening Test, Second Edition, and the Screening Tool for Autism in Two-year-olds. The development of the M-CHAT, a Level I and Level II screening instrument, is described, and current research and clinical use of the M-CHAT are reviewed, including description of the structured follow-up interview which reduces the false-positive rate of the parent-report M-CHAT.

Autistic Disorder↗

PubMed2002

Early recognition of 1-year-old infants with autism spectrum disorder versus mental retardation.

Previous work based on observations of home videotapes indicates that differences can be detected between infants with autism spectrum disorder and infants with typical development at 1 year of age. The present study addresses the question of whether autism can be distinguished from mental retardation by 1 year of age. Home videotapes of first birthday parties from 20 infants later diagnosed with autism spectrum disorder, 14 infants later diagnosed with mental retardation (without autism), and 20 typically developing infants were coded by blind raters with respect to the frequencies of specific social and communicative behaviors and repetitive motor actions. Results indicated that 1-year-olds with autism spectrum disorder can be distinguished from 1-year-olds with typical development and those with mental retardation. The infants with autism spectrum disorder looked at others and oriented to their names less frequently than infants with mental retardation. The infants with autism spectrum disorder and those with mental retardation used gestures and looked to objects held by others less frequently and engaged in repetitive motor actions more frequently than typically developing infants. These results indicate that autism can be distinguished from mental retardation and typical development by 1 year of age.

Autistic Disorder↗

PubMed1999

A screening questionnaire for Asperger syndrome and other high-functioning autism spectrum disorders in school age children.

The high-functioning Autism Spectrum Screening Questionnaire (ASSQ) is a 27-item checklist for completion by lay informants when assessing symptoms characteristic of Asperger syndrome and other high-functioning autism spectrum disorders in children and adolescents with normal intelligence or mild mental retardation. Data for parent and teacher ratings in a clinical sample are presented along with various measures of reliability and validity. Optimal cutoff scores were estimated, using Receiver Operating Characteristic analysis. Findings indicate that the ASSQ is a useful brief screening device for the identification of autism spectrum disorders in clinical settings.

Adolescent↗