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PubMed2005

Source memory in children with autism spectrum disorders.

The evidence to date regarding memory processes in children with autism spectrum disorders (ASD) remains equivocal. Although children with these neurodevelopmental disorders have been shown to display exceptional memories for fact-based information, they seem to be less able to attach meaning or context to their memories. Thus, this study investigated the specific role of source memory in autism. Children with ASD were compared to a chronological and mental age-matched comparison group of typically developing children. Although children with autism performed similarly to controls on a fact recognition measure, their performance on a source memory task was significantly lower. The findings indicated, however, that the nature of source memory confusion in children with autism does not appear to reflect a generalized deficit in attaching context to memories but rather is dependent on the specific to-be-remembered information that, in this study, involves social aspects of context.

Adolescent↗

PubMed2002

Enzyme-based therapy for autism spectrum disorders -- is it worth another look?

Autism is a developmental disease usually manifesting within the first three years of life. To date, no causative agent has been found. Similarly, treatment options have been limited. Of the treatment options available, a number of them have been nutritionally based in an attempt to address one or more of the theories regarding the etiology of the disease. An example would be enzyme therapy for the digestion of purported offending neuroactive peptides collectively known as exorphins. This paper discusses the exorphin theory of autism and subsequent treatment with dietary enzyme therapy. Novel data are presented in support of the theory that enzymes play a critical role in autism. Forty-six patients between the ages of 5 and 31 were selected for inclusion in the study based on a diagnosis placing them in the category of the autism spectrum disorders (ASD). The diets were supplemented with a novel dietary enzyme formulation, ENZYMAID, for a period of 12 weeks. Progress was tracked according to the Symptom Outcome Survey (SOS) (1) form method of symptom charting and presented in a table for further analysis. The novel enzyme formula, ENZYMAID, beneficially and safely affected all 13 of the parameters measured. Improvements ranged from 50-90%, depending on the parameter measured. Enzyme therapy to treat ASD may indeed a viable option in treatment protocols. These results indicate that further controlled studies are warranted.

Adolescent↗

PubMed2005

Individuals with autism spectrum disorder show normal responses to a fear potential startle paradigm.

The present study utilized a fear potentiated startle paradigm to examine amygdala function in individuals with autism spectrum disorder. Two competing hypotheses regarding amygdala dysfunction in autism have been proposed: (1) The amygdala is under-responsive, in which case it would be predicted that, in a fear potentiated startle experiment, individuals with autism would exhibit decreased fear conditioning and/or potentiation, and (2) The amygdala is over responsive, in which case an exaggerated potentiation of the startle response would be predicted. Fourteen adolescents and adults diagnosed with autism spectrum disorder and 14 age, gender, IQ, and anxiety level-matched typical adolescents and adults participated. Both participants with autism and typical participants potentiated the startle response following fear conditioning and no group differences in the latency or amplitude of the potentiated startle response were found. These results suggest that this aspect of amygdala function, namely fear conditioning and potentiation of the startle response, is intact in individuals with autism.

Adolescent↗

PubMed2006

Autism spectrum disorders and underlying brain pathology in CHARGE association.

The rate of autism spectrum disorders (ASDs) and brain abnormalities was analyzed in 31 individuals (15 males, 16 females; age range 1mo to 31y, mean age 8y 11mo) with CHARGE association, as part of a multidisciplinary study. A meticulous neuropsychiatric examination was performed, including standardized autism diagnostic interviews. Judgement regarding ASDs was impossible in three infants and three patients who were deaf and blind. Five individuals met diagnostic criteria for autism, five for an autistic-like condition, and seven for autistic traits. Brain abnormalities were indicated in almost three-quarters of examined individuals, and midline abnormalities of the forebrain in one-third. Awareness of the coexistence of CHARGE and ASDs is important in habilitation care in CHARGE. Moreover, the results indicate that a subgroup of ASDs may be associated with errors in early embryonic brain development.

Abnormalities, Multiple↗

PubMed2005

Perceptions of social challenges of adults with autism spectrum disorder.

This study examines perceptions of social challenges by adults with autism spectrum disorder (ASD). The investigators analyzed three separate, regularly scheduled social group meetings attended by a total of 18 adults with ASD where the activity was a discussion of social issues. Participants generated social questions and challenges they had encountered as a result of having autism. The questions were presented to the group for a discussion of potential solutions. Written and audio data were collected and a member check was completed. The data were plumbed for key words and emergent themes to identify major social challenges as viewed by adults with ASD. The emergent themes included relationships at work, developing and maintaining personal relationships, appropriate behaviors around members of the opposite sex, and personal perspectives on having ASD.

Adult↗

PubMed2006

Diagnostic yield in the clinical genetic evaluation of autism spectrum disorders.

PURPOSE: Clinical geneticists are often asked to evaluate patients with autism spectrum disorders (ASDs) in reference to questions about cause and recurrence risk. Recent advances in diagnostic testing technology have greatly increased the options available to them. It is not currently clear what the overall diagnostic yield of a battery of tests, either collectively or individually, might be. The purpose of this study was to evaluate the diagnostic yield of a stepwise approach we have implemented in our clinics. METHODS: We used a three-tiered neurogenetic evaluation scheme designed to determine the cause of ASDs in patients referred for clinical genetic consultation. We reviewed the results of our diagnostic evaluations on all patients referred with a confirmed diagnosis of autism over a 3-year period. RESULTS: By using this approach, we found an overall diagnostic yield for ASDs of more than 40%. This represents a significant increase in the diagnostic yield reported just a few years ago. CONCLUSIONS: Given the implications of these diagnoses on recurrence risk and associated medical conditions, a targeted neurogenetic evaluation of all persons with ASDs seems warranted. We discuss the issues in the future implementation of a fourth tier to the evaluation with the potential for an even higher diagnostic yield.

Autistic Disorder↗

PubMed2024

Rare variation in non-coding regions with evolutionary signatures contributes to autism spectrum disorder risk.

Little is known about the role of non-coding regions in the etiology of autism spectrum disorder (ASD). We examined three classes of non-coding regions: human accelerated regions (HARs), which show signatures of positive selection in humans; experimentally validated neural VISTA enhancers (VEs); and conserved regions predicted to act as neural enhancers (CNEs). Targeted and whole-genome analysis of >16,600 samples and >4,900 ASD probands revealed that likely recessive, rare, inherited variants in HARs, VEs, and CNEs substantially contribute to ASD risk in probands whose parents share ancestry, which enriches for recessive contributions, but modestly contribute, if at all, in simplex family structures. We identified multiple patient variants in HARs near IL1RAPL1 and in VEs near OTX1 and SIM1 and showed that they change enhancer activity. Our results implicate both human-evolved and evolutionarily conserved non-coding regions in ASD risk and suggest potential mechanisms of how regulatory changes can modulate social behavior.

Humans↗

PubMed2002

The prevalence of autism spectrum disorders. Recent evidence and future challenges.

BACKGROUND: Until recently best estimate prevalence rates for autism spectrum disorders (ASD) were 0.5/1,000 for autism and 2.0/1,000 for the broader spectrum. Three recent studies have suggested a significantly higher prevalence rate for ASD of 6.0/1,000 (mean 95 % CI = 4.8-8.0). METHOD: Possible determinants of the apparent increase in the prevalence of ASD are outlined. Methodological aspects of the three recent studies are examined. FINDINGS: Increased recognition, the broadening of the diagnostic concept over time and methodological differences across studies may account for most or all of the apparent increase in prevalence, although this cannot be quantified. CONCLUSIONS: Findings from ongoing studies should help confirm or disconfirm the putative rate of 6.0/1,000 for all ASD. The possibility that autism has been over-diagnosed in recent studies needs to be ruled out. Notwithstanding these outstanding questions, it appears likely that the current true prevalence of ASD is considerably greater than previously recognised. This has significant implications for our scientific understanding of ASD and for families and services. Future directions for epidemiological research are outlined.

Adolescent↗

PubMed2003

Routine cytogenetic and FISH studies for 17p11/15q11 duplications and subtelomeric rearrangement studies in children with autism spectrum disorders.

To assess the frequency of cytogenetic abnormalities in children with autism spectrum disorders (ASDs), routine G-banded cytogenetic analyses and FISH studies to rule out 15q11.2 and 17p11.2 duplications were performed on 49 children with ASDs. Blood samples were further studied using a complete set of subtelomeric FISH probes. Routine chromosome study showed that one child had a small duplication of chromosome 5: 46,XY,dup(5)(p?14.2p?15.1). Another child had an interstitial duplication of the Prader-Willi and Angelman syndrome critical region of chromosome 15, detected by FISH analysis. The detection of these two cases underscores the importance of obtaining routine chromosome and 15q11-q13 FISH analyses in children with ASDs. No instance of 17p11.2 duplication was observed. Subtelomeric analysis did not reveal abnormalities in any of the subjects.

Adolescent↗

PubMed2006

Affect regulation and temperament in children with Autism Spectrum Disorder.

Affect regulation (AR) and temperament were examined in children with Autism Spectrum Disorder (ASD). To determine AR, children were exposed to a mildly frustrating situation. Temperament was assessed by the Children's Behavior Questionnaire (CBQ). Children with ASD showed greater variability in AR and used less effective AR strategies compared to controls. Lower academic ability was associated with less effective AR strategies for the ASD while for the controls older age predicted more effective AR strategies. Those with ASD were lower than controls in Attention Focusing, Inhibitory Control, and Soothability. Of the three overarching temperament factors of the CBQ, only Effortful Control but not Negative Affectivity and Surgency/Extraversion distinguished those with ASD from controls. For the ASD group, higher academic ability predicted higher Negative Affectivity. Fewer symptoms and older chronological age predicted higher Effortful Control.

Achievement↗

PubMed2007

Hyperlexia in children with autism spectrum disorders.

We compared the reading-related skills of children with Autism Spectrum Disorders who have hyperlexia (ASD + HPL) with age-matched children with ASD without HPL (ASD - HPL) and with single-word reading-matched typically developing children (TYP). Children with ASD + HPL performed (1) better than did children with ASD - HPL on tasks of single-word reading and pseudoword decoding and (2) equivalently well compared to word-reading-matched TYP children on all reading-related tasks except reading comprehension. It appears that the general underlying model of single-word reading is the same in principle for "typical" and hyperlexic reading. Yet, the study revealed some dissimilarities between these two types of reading when more fine-grained cognitive and linguistic abilities were considered; these dissimilarities warrant further investigations.

Adolescent↗

PubMed2006

Effects of social stories on prosocial behavior of preschool children with autism spectrum disorders.

Social Stories are a popular intervention for preschool children with autism spectrum disorders (ASD), but little research on Social Stories has been conducted with this population. This study investigated the effects of Social Stories on prosocial behavior of three preschool children with ASD in an inclusive setting. An ABAB design was used for two participants, while an ABACBC was used for the third. Social Stories increased appropriate behavior and decreased inappropriate behavior for two participants. The addition of verbal prompts (condition C) was necessary to increase appropriate behavior for the third participant. Maintenance probes were conducted to assess whether stories became imbedded in classroom routines. Results are discussed in relation to applications, study limitations, and areas for future research.

Autistic Disorder↗

PubMed2005

Autism spectrum disorders in Prader-Willi and Angelman syndromes: a systematic review.

Autism spectrum disorders (ASDs) have been linked with maternally derived duplications/triplications of chromosome 15q11-13 and therefore might occur more frequently in people with Prader-Willi syndrome (PWS) when due to uniparental disomy (UPD), than in other forms of chromosomal abnormality involving this region [i.e. deletion (DEL) forms of PWS and DEL+UPD forms of Angelman's syndrome -(AS)]. Twelve studies regarding ASD in PWS and AS were reviewed. It was noteworthy that among the genetically confirmed UPD and DEL cases of PWS and AS, the rate of ASD was 25.3% (38/150; range 0-36.5%) in PWS and 1.9% in AS (2/104; range 0-100%) (Fisher's exact P<0.0001). Among the subset of cases with confirmed UPD or DEL, the rate of ASD in the UPD cases of PWS was significantly higher (20/53) than in the remaining combined samples (i.e. DEL PWS+UPD AS+DEL AS cases; 20/201) (Fisher's exact P<0.0001). ASD in UPD PWS cases (20/53) compared with DEL PWS cases (18/97) was also statistically significant (Fisher's exact P=0.0176). Thus, the limited available evidence supported the prediction that overexpression of maternally imprinted genes in 15q11-13 confers a risk for ASD. Further research will be required to confirm these findings.

Angelman Syndrome↗

PubMed2006

Effects of season of birth on autism spectrum disorders: fact or fiction?

OBJECTIVE: This study attempted to examine the relationship between month and season of birth and risk for autism spectrum disorders. METHOD: The cohort included all Jewish individuals born in Israel over 5 consecutive years (N=311,169) and assessed by the Israeli Draft Board as part of the mandatory assessment of eligibility for military service conducted at age 17. The outcome of autism spectrum disorders was ascertained from the Draft Board Medical Registry, which contains information about medical and psychiatric disorders for this population of adolescents. RESULTS: There was no association between month or season of birth and the prevalence of autistic spectrum disorders. CONCLUSIONS: The findings from this historical, population-based cohort study do not support an association between season of birth and autistic spectrum disorders.

Adolescent↗

PubMed2006

Combining information from multiple sources in the diagnosis of autism spectrum disorders.

BACKGROUND: Standard case criteria are proposed for combined use of the Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule to diagnose autism and to define the broader category of autism spectrum disorders. METHOD: Single and combined Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule algorithms were compared to best estimate diagnoses in four samples: U.S. (n = 960) and Canadian (n = 232) participants 3 years and older, U.S. participants younger than 36 months (n = 270), and U.S. participants older than 36 months with profound mental retardation (n = 67). RESULTS: Sensitivities and specificities of 80% and higher were obtained when strict criteria for an autism diagnosis using both instruments were applied in the U.S. samples, and 75% or greater in the Canadian sample. Single-instrument criteria resulted in significant loss of specificity. Specificity was poor in the sample with profound mental retardation. Lower sensitivity and specificity were also obtained when proposed criteria for broader spectrum disorders were applied. CONCLUSIONS: The Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule make independent, additive contributions to the judgment of clinicians that result in a more consistent and rigorous application of diagnostic criteria.

Asperger Syndrome↗

PubMed2006

Autism spectrum disorders and attention-deficit/hyperactivity disorder in boys with the fragile X premutation.

Fragile X syndrome (FXS) is caused by a full mutation expansion (>200 CGG repeats) in the FMR1 gene that results in a deficiency of the fragile X mental retardation protein. Although most individuals with the premutation (55-200 CGG repeats) are considered unaffected by FXS, recent case studies have documented children with the premutation who have cognitive deficits, behavioral problems, and/or autism spectrum disorders. The objective of this study was to compare the prevalence of autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD) symptoms in boys with the premutation who presented as probands, in brothers with the premutation who did not present as probands, and in normal brothers of premutation and/or full mutation carriers. Participants included 43 male children: 14 probands who presented to clinic, 13 nonprobands who were identified through cascade testing (routine genetic testing of family members after identification of a proband) and confirmed to have the premutation, and a control group of 16 male siblings of individuals with the fragile X premutation or full mutation who were negative for the FMR1 mutation. Participants came from 1 of 2 collaborative sites: University of California, Davis and La Trobe University in Australia. Parents completed the Conners' Global Index-Parent Version for assessing symptoms of ADHD and the Social Communication Questionnaire (SCQ) for identifying symptoms of ASD. Children who were in the ASD range on the SCQ (n = 13) underwent further evaluation with either the Autism Diagnostic Observation Schedule-Generic (n = 10) or the Autism Diagnostic Interview-Revised (n = 3). A final diagnosis of ASD included clinical assessment utilizing DSM-IV-TR criteria in addition to the standardized assessments. There was a higher rate of ASD in boys with the premutation presenting as probands (p < 0.001) or nonprobands (p < .04) compared with sibling controls without the premutation. In addition, probands had a significant increase in ADHD symptoms compared with controls (p < .0001). Of the probands, 93% had symptoms of ADHD and 79% had ASD. In the nonproband premutation group, 38% had symptoms of ADHD and 8% had ASD. Thirteen percent of sibling controls had symptoms of ADHD and none had ASD. IQ scores were similar in all 3 groups (p = .13), but the use of psychotropic medications was significantly higher in probands with the premutation compared with that in controls (p < .0001). Developmental problems have been observed in premutation carriers, particularly those who present clinically with behavioral difficulties. Although this study is based on a small sample size, it suggests that premutation carriers, even those who do not present clinically, may be at increased risk for an ASD and/or symptoms of ADHD. If the premutation is identified through cascade testing, then further assessment should be carried out for symptoms of ADHD, social deficits, or learning disabilities.

Adolescent↗

PubMed2004

A possible association between fetal/neonatal exposure to radiofrequency electromagnetic radiation and the increased incidence of autism spectrum disorders (ASD).

Recently disclosed epidemiological data indicate a dramatic increase in the incidence of autism spectrum disorders. Previously, the incidence of autism has been reported as 4-5 per 10000 children. The most recent evidence indicates an increased incidence of about 1 per 500 children. However, the etiology of autism is yet to be determined. The recently disclosed data suggest a possible correlation between autism incidence and a previously unconsidered environmental toxin. It is generally accepted in the scientific community that radiofrequency (RF) radiation is a biologically active substance. It is also readily acknowledged that human exposures to RF radiation have become pervasive during the past 20 years, whereas such exposures were uncommon prior to that time. It is suggested that fetal or neo-natal exposures to RF radiation may be associated with an increased incidence of autism.

Autistic Disorder↗

PubMed2025

Autism spectrum disorder risk genes have convergent effects on transcription and neuronal firing patterns in primary neurons.

Autism spectrum disorder (ASD) is a highly heterogenous neurodevelopmental disorder with numerous genetic risk factors. Notably, a disproportionate number of risk genes encode transcription regulators including transcription factors and proteins that regulate chromatin. Here, we test the function of nine such ASD-linked transcription regulators by depleting them in primary cultured neurons. We then define the resulting gene expression disruptions using RNA sequencing and test effects on neuronal firing using multielectrode array recordings. We identify shared gene expression signatures across many ASD risk genes that converge on the disruption of critical synaptic genes. Fitting with this, we detect robust disruptions to neuronal firing throughout neuronal maturation. Together, these findings provide evidence that the loss of multiple ASD-linked transcriptional regulators disrupts transcription of synaptic genes and has convergent effects on neuronal firing that may contribute to enhanced ASD risk.

Autism Spectrum Disorder↗