Autism spectrum disorder diagnoses in Stockholm preschoolers

The occurrence of challenging behaviours in children with autism spectrum disorders and atypical development

OBJECTIVE

This study examines the occurrence of challenging behaviours in children with ASDs and atypical development.

DESIGN

This study is a descriptive non-experimental design that inspects the frequencies of challenging behaviours among two diagnostic groups. This type of methodology is important since research in this area is still in the beginning stages of development.

METHODS

The sample consisted of 2131 children, with 633 having an ASD and 1498 having atypical development. The Baby and Infant Screen for Children with aUtIsm Traits-Part 3 (BISCUIT-Part 3) assesses problematic behaviours within this population. The frequencies of challenging behaviours were examined along with an inspection of the co-occurring items.

RESULTS

Greater percentages of problematic behaviours were found in the ASD group as compared to the group with atypical development.

CONCLUSION

Challenging behaviours are variables affecting the behavioural presentation of those with ASDs and may be considered into the treatment plans for these children.

Psychopathology and intellectual disability

PURPOSE OF REVIEW

To provide an update on recent trends and developments in the study of psychopathology in persons with intellectual disability. This topic is of considerable importance to mental health professionals as rates of psychopathology are much higher for persons with intellectual disabilities relative to the general population.

RECENT FINDINGS

The number of studies on this topic is growing. The development of several areas is of particular significance. These topics include the impact of the burgeoning study of autism; the development of more specialized measures of psychopathology specific to particular forms of psychopathology, levels of intellectual disability and age; the development of psychologically based treatments, specifically the rise of functional assessment; the recognition that pharmacotherapy treatments are best aimed at core symptoms of classic forms of psychopathology such as psychosis, bipolar disorder, anxiety, and depression versus behavioral equivalents of psychopathology such as aggression, self-injurious behavior, property destruction, and pica; and establishing co-occurring patterns of personal features as they relate to psychopathology and intellectual disability.

SUMMARY

A better understanding of psychopathology and how to assess and treat it in persons with intellectual disability is occurring. However, much is yet to be learned in this relatively new field of study.

Psychiatric comorbidity in young adults with a clinical diagnosis of Asperger syndrome

In children with autism spectrum disorders, previous studies have shown high rates of psychiatric comorbidity. To date, studies on adults have been scarce. The aim of the present study was to investigate psychiatric comorbidity in young adults with Asperger syndrome. Participants were 26 men and 28 women (mean age 27 years) with a clinical diagnosis of Asperger syndrome. Psychiatric comorbidity was assessed by the Structured Clinical Interview for DSM-IV Axis I Disorders. IQ was measured using the Wechsler Adult Intelligence Scale, Third Edition. Autism spectrum diagnoses were confirmed using the DIagnostic Interview for Social and Communication Disorders. In our study group, 70% had experienced at least one episode of major depression, and 50% had suffered from recurrent depressive episodes. Anxiety disorders were seen in about 50%. Psychotic disorders and substance-induced disorders were uncommon. In conclusion, young adults with autism spectrum disorders are at high risk for mood and anxiety disorders. To identify these conditions and offer treatment, elevated vigilance is needed in clinical practice.

Parents' first concerns of their child's development in toddlers with autism spectrum disorders

OBJECTIVE

Investigations about first concerns among parents of toddlers with ASD and comparisons of the same with children diagnosed with other developmental disorders are scarce.

METHOD

The current study utilized a sample of toddlers diagnosed with an ASD or other developmental delay and examined the nature of parents' first concern and the age of first concern compared to the age of first assessment.

RESULTS

The majority of parents of both toddlers diagnosed with ASD and non-ASD related developmental delays indicated that the area of first concern was in communication. However, the age of first concern was significantly younger for toddlers with an ASD diagnosis. In addition, there was a significant positive correlation between the age at which concerns were first noted and the age at which assessment was sought.

CONCLUSION

The implications of these findings are discussed as they relate to early assessment and intervention.

Function and neuroimaging in cerebral palsy: a population-based study

AIM

The aim of this population-based study was to describe function in cerebral palsy (CP) in relation to neuroimaging.

METHOD

Motor function, accompanying impairments, and neuroimaging (86 by magnetic resonance imaging, 74 by computed tomography) were studied in 186 children born in western Sweden between 1999 and 2002 (96 males, 90 females; age range at data collection 4-8 y). results: Forty per cent of the children had unilateral spastic CP, 39% bilateral, 16% dyskinetic CP, and 5% ataxia. Fifty-one per cent were in level I of the Gross Motor Function Classification System (GMFCS), 14% in level II, 3% in level III, 11% in level IV, and 22% level V. Forty per cent of the children were in level I of the Manual Ability Classification System 19% were in II, 9% at III, 8% in IV, and 24% in level V. Seventy-six per cent of the children with white-matter lesions were in GMFCS levels I and II, whereas 67% with basal ganglia lesions were in levels IV and V. Learning disability* (45%), epilepsy (44%), and visual impairment (17%) were most common in children with brain maldevelopment, and cortical/subcortical or basal ganglia lesions. Speech was impaired in 49% of the children, absent in 30%, and 6% had a neuropsychiatric diagnosis. Compared with children born between 1991 and 1998, the numbers of those in GMFCS level I increased (p=0.007), as did those with epilepsy (p=0.015).

INTERPRETATION

Neuroimaging improves the understanding of the neuroanatomical basis for function in CP. Type and severity of motor impairment and accompanying impairments are related to the timing of lesions.

Gene-ontology enrichment analysis in two independent family-based samples highlights biologically plausible processes for autism spectrum disorders

Recent genome-wide association studies (GWAS) have implicated a range of genes from discrete biological pathways in the aetiology of autism. However, despite the strong influence of genetic factors, association studies have yet to identify statistically robust, replicated major effect genes or SNPs. We apply the principle of the SNP ratio test methodology described by O'Dushlaine et al to over 2100 families from the Autism Genome Project (AGP). Using a two-stage design we examine association enrichment in 5955 unique gene-ontology classifications across four groupings based on two phenotypic and two ancestral classifications. Based on estimates from simulation we identify excess of association enrichment across all analyses. We observe enrichment in association for sets of genes involved in diverse biological processes, including pyruvate metabolism, transcription factor activation, cell-signalling and cell-cycle regulation. Both genes and processes that show enrichment have previously been examined in autistic disorders and offer biologically plausibility to these findings.

Feeding Therapy in a Child With Autistic Disorder: Sequential Food Presentation

The authors describe a feeding intervention for a 9-year-old male diagnosed with autistic disorder and mild mental retardation (also known as intellectual disability) who experienced food refusal related to food selectivity. Based on the results of a functional behavioral assessment, food refusal was found to be maintained by escape and tangible functions. Therefore, an intervention using escape extinction (i.e., nonremoval of nonpreferred foods with physical guidance as a secondary procedure), positive reinforcement (i.e., preferred foods and toys), and sequential food presentation was implemented. The child was successful in eating many novel foods both within the clinic and home environments. A 1-year follow-up found the effects of treatment to be maintained with significant increases in number of foods eaten and significant decreases in mealtime-related behavioral challenges. The treatment implications, recommendations to clinicians, and areas of future research are discussed.

Structural and functional magnetic resonance imaging of autism spectrum disorders

The neurobiology of autism spectrum disorders (ASDs) has become increasingly understood since the advent of magnetic resonance imaging (MRI). Initial observations of an above-average head circumference were supported by structural MRI studies that found evidence of increased total brain volume and early rapid brain overgrowth in affected individuals. Subsequent research revealed consistent abnormalities in cortical gray and white matter volume in ASDs. The structural integrity and orientation of white matter have been further elucidated via diffusion tensor imaging methods. The emergence of functional MRI techniques led to an enhanced understanding of the neural circuitry of ASDs, demonstrating areas of dysfunctional cortical activation and atypical cortical specialization. These studies have provided evidence of underconnectivity in distributed cortical networks integral to the core impairments associated with ASDs. Abnormalities in the default-mode network during the resting state have also been identified. Overall, structural and functional MRI research has generated important insights into the neurobiology of ASDs. Additional research is needed to further delineate the underlying brain basis of this constellation of disorders.

Variations of the candidate SEZ6L2 gene on Chromosome 16p11.2 in patients with autism spectrum disorders and in human populations

BACKGROUND

Autism spectrum disorders (ASD) are a group of severe childhood neurodevelopmental disorders with still unknown etiology. One of the most frequently reported associations is the presence of recurrent de novo or inherited microdeletions and microduplications on chromosome 16p11.2. The analysis of rare variations of 8 candidate genes among the 27 genes located in this region suggested SEZ6L2 as a compelling candidate.

METHODOLOGY/PRINCIPAL FINDINGS

We further explored the role of SEZ6L2 variations by screening its coding part in a group of 452 individuals, including 170 patients with ASD and 282 individuals from different ethnic backgrounds of the Human Genome Diversity Panel (HGDP), complementing the previously reported screening. We detected 7 previously unidentified non-synonymous variations of SEZ6L2 in ASD patients. We also identified 6 non-synonymous variations present only in HGDP. When we merged our results with the previously published, no enrichment of non-synonymous variation in SEZ6L2 was observed in the ASD group compared with controls.

CONCLUSIONS/SIGNIFICANCE

Our results provide an extensive ascertainment of the genetic variability of SEZ6L2 in human populations and do not support a major role for SEZ6L2 sequence variations in the susceptibility to ASD.

Do common variants play a role in risk for autism? Evidence and theoretical musings

Both rare and common genetic variants underlie risk for almost any complex disease. Over the past few years a common tool for identifying common risk variants is genome-wide association or GWA. Our analyses focus on results from GWA targeting common variants affecting risk for autism spectrum disorders (ASD). Thus far three large GWA studies have been published, each of which highlights a single, non-overlapping risk locus. Evaluation of these studies suggests that combination of their data would diminish evidence for all of these loci, making none of them significant. Despite this paucity of findings, statistical theory can be used to infer a plausible distribution of effect sizes for SNPs affecting risk for ASD. We lay out this theory, calculate plausible distributions, and discuss the results in the context of results from GWA studies for schizophrenia.

A genome-wide scan for common alleles affecting risk for autism

Although autism spectrum disorders (ASDs) have a substantial genetic basis, most of the known genetic risk has been traced to rare variants, principally copy number variants (CNVs). To identify common risk variation, the Autism Genome Project (AGP) Consortium genotyped 1558 rigorously defined ASD families for 1 million single-nucleotide polymorphisms (SNPs) and analyzed these SNP genotypes for association with ASD. In one of four primary association analyses, the association signal for marker rs4141463, located within MACROD2, crossed the genome-wide association significance threshold of P < 5 × 10⁻⁸. When a smaller replication sample was analyzed, the risk allele at rs4141463 was again over-transmitted; yet, consistent with the winner's curse, its effect size in the replication sample was much smaller; and, for the combined samples, the association signal barely fell below the P < 5 × 10⁻⁸ threshold. Exploratory analyses of phenotypic subtypes yielded no significant associations after correction for multiple testing. They did, however, yield strong signals within several genes, KIAA0564, PLD5, POU6F2, ST8SIA2 and TAF1C.

Key role for gene dosage and synaptic homeostasis in autism spectrum disorders

Autism spectrum disorders (ASD) are characterized by impairments in reciprocal social communication, and repetitive, stereotyped verbal and non-verbal behaviors. Genetic studies have provided a relatively large number of genes that constitute a comprehensive framework to better understand this complex and heterogeneous syndrome. Based on the most robust findings, three observations can be made. First, genetic contributions to ASD are highly heterogeneous and most probably involve a combination of alleles with low and high penetrance. Second, the majority of the mutations apparently affect a single allele, suggesting a key role for gene dosage in susceptibility to ASD. Finally, the broad expression and function of the causative genes suggest that alteration of synaptic homeostasis could be a common biological process associated with ASD. Understanding the mechanisms that regulate synaptic homeostasis should shed new light on the causes of ASD and could provide a means to modulate the severity of the symptoms.