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

Mutations associated with autism lead to similar synaptic and behavioral alterations in both sexes of male and female mouse brain

Autism spectrum disorder (ASD) is a neurodevelopmental disorder based on synaptic abnormalities. The estimated prevalence rate of male individuals diagnosed with ASD prevails over females is in a proportion of 4:1. Consequently, males remain the main focus in ASD studies in clinical and experimental settings. Meanwhile, some studies point to an underestimation of this disorder in females. In this work, we studied the sex differences of the synaptic and behavioral phenotypes of ASD mouse models. Juvenile male and female Shank3Δ4-22 and Cntnap2-/- mutant mice and their WT littermates were used in the experiments. The animals were subjected to a Three-Chamber Sociability Test, then euthanized, and the whole cortex was used for the evaluation of the synaptic phenotype. Protein levels of glutamatergic (NR1) and GABAergic (GAD1 and VGAT) neuronal markers were measured. Protein level of synaptophysin (Syp) was also measured. Dendritic spine density in somatosensory neurons was analyzed by Golgi staining methods. Spine Density and GAD1, NR1, VGAT, and Syp levels were significantly reduced in Shank3Δ4-22 and Cntnap2-/- mice compared to the control group irrespective of sex, indicating impaired synaptic development in the mutant mice. These results were consistent with the lack of differences in the three-chamber sociability test between male and female mice. In conclusion, female ASD mice of both mutations undergo similar synaptic aberrations as their male counterparts and need to be studied along with the male animals. Finally, this work urges the psychiatry scientific community to use both sexes in their investigations.

Risk factors and clinical profile of autism spectrum disorder in southern Brazil

In Brazil, as in other countries, it is expected a significant variation of epidemiological and clinical characteristics among individuals with autism spectrum disorder (ASD). This study was performed to explore maternal risk factors and clinical characteristics of children with ASD in a population located in southern Brazil. Data were collected from medical records and analyzed to explore biomarkers associated with ASD. Out of 321 children with ASD, 86.5% were males with a male-to-female ratio of 5.7:1, 50.7% were mild/moderate while 49.3% presented severe ASD. Between the risk factors investigated, gestational infection was significantly associated with severe ASD patients. There was also an association between epilepsy and severe autism. Several gastrointestinal (GI) symptoms were significantly associated with severe ASD. Obesity, followed by lower levels of cholesterol, were also significant factors associated with an ASD diagnosis when compared to age-matched controls. Finally, severe ASD was associated with significantly higher serum serotonin levels when compared to age-matched controls and mild/moderate ASD cases. Our findings demonstrate that our population shares many features associated with ASD around the world, such as GI symptoms, epilepsy, and high serotonin levels. It is worth highlighting the low cholesterol levels associated with obesity as an unusual feature that deserves more attention.

[Assessment of the importance of neuropediatric diagnostics in the initial clarification of autism]

BACKGROUND

The diagnostics of autism spectrum disorder is complex due to missing biological markers and numerous comorbidities. The aim was to assess the role of neuropediatric diagnostics and to develop a standard operating procedure for a targeted assessment.

METHOD

All patients presenting to the neuropediatric outpatient clinic at Saarland University Hospital between April 2014 and December 2017 with ICD code F84 pervasive developmental disorders were included.

RESULTS

A total of 82 patients were included (male 78%, female 22%; mean age 5.9 ± 2.9 years, range 2-16 years). The most frequent examination was electroencephalography (EEG) (74/82; 90.2%) with pathological findings in 33.8% (25/74). Based on the history and/or EEG epilepsy was diagnosed in 19.5% (16/82). Magnetic resonance imaging (MRI) was performed in 49/82 (59.8%) patients, 22/49 (44.9%) showed at least 1 cerebral abnormality and definite pathologies could be detected in 63.6% (14/22). A metabolic diagnostic work-up was performed in 44/82 (53.7%) cases and in 5/44 (11.4%) it resulted in a diagnosis or suspicion of a metabolic disease. Genetic testing results were available in 29/82 (35.4%) children and 12/29 (41.4%) showed abnormal results. Delay in motor development was more frequently associated with comorbidities, EEG abnormalities, epilepsy and abnormalities in metabolic and genetic testing.

CONCLUSION

Neuropediatric examination in cases of suspected autism should include a detailed history, a thorough neurological examination and an EEG. An MRI, comprehensive metabolic and genetic testing are only recommended if clinically indicated.

The global prevalence of autism spectrum disorder: a comprehensive systematic review and meta-analysis

Background

Autism spectrum disorder (ASD) is one of the serious developmental disorders that is usually diagnosed below the age of three years. Although the severity of the disease’s symptoms varies from patient to patient, the ability to communicate with others is affected in all forms of ASD. This study aimed to determine the prevalence of ASD in high-risk groups by continent.

Methods

The present study was conducted by systematic review and meta-analysis from 2008 to July 2021. Databases such as Science Direct, PubMed, Scopus, SID, Magiran, Web of Science (WoS), and Google Scholar from 2008 to July 2021 were searched to find related studies. Data were analysed using Comprehensive Meta-Analysis software (Version 2).

Results

A total of 74 studies with 30,212,757 participants were included in this study. The prevalence of ASD in the world was 0.6% (95% confidence interval: 0.4–1%). Subgroup analyses indicated that the prevalence of ASD in Asia, America, Europe, Africa and Australia was 0.4% (95% CI: 0.1–1), 1% (95% CI: 0.8–1.1), 0.5% (95% CI: 0.2–1), 1% (95% CI: 0.3–3.1), 1.7% (95% CI: 0.5–6.1) respectively.

Conclusion

ASD imposes a heavy health burden on communities around the world. Early detection of ASD can reduce the incidence of developmental disorders and improve patients’ communication skills. Therefore, health policymakers need to be aware of the prevalence and increasing trend of ASD to implement appropriate planning and interventions to reduce its consequences.

Sex Differences in Autism Spectrum Disorder: Diagnostic, Neurobiological, and Behavioral Features

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with a worldwide prevalence of about 1%, characterized by impairments in social interaction, communication, repetitive patterns of behaviors, and can be associated with hyper- or hypo-reactivity of sensory stimulation and cognitive disability. ASD comorbid features include internalizing and externalizing symptoms such as anxiety, depression, hyperactivity, and attention problems. The precise etiology of ASD is still unknown and it is undoubted that the disorder is linked to some extent to both genetic and environmental factors. It is also well-documented and known that one of the most striking and consistent finding in ASD is the higher prevalence in males compared to females, with around 70% of ASD cases described being males. The present review looked into the most significant studies that attempted to investigate differences in ASD males and females thus trying to shade some light on the peculiar characteristics of this prevalence in terms of diagnosis, imaging, major autistic-like behavior and sex-dependent uniqueness. The study also discussed sex differences found in animal models of ASD, to provide a possible explanation of the neurological mechanisms underpinning the different presentation of autistic symptoms in males and females.

Quality of life in adults with autism spectrum disorder: influence of age, sex, and a controlled, randomized mindfulness-based stress reduction pilot intervention

PURPOSE

Adults with autism spectrum disorder (ASD) consistently report worse functional health and well-being, compared to neurotypical (NT) peers. In a series of studies, we aimed to elucidated the effects of sex, age, and their interaction on health-related quality of life (HRQoL) and evaluated the effectiveness of mindfulness-based stress reduction (MBSR) for improving health-, disability-, and autism-related QoL, with possible sex and age outcome moderators, in adults with ASD.

METHODS

Study 1 used the 36-Item Short Form Survey to compare mental and physical HRQoL composite scores in adults with ASD (n = 67) and matched NT adults (n = 66). Study 2 was a randomized pilot evaluation of the effect of MBSR, compared to an active control intervention with social support and relaxation education (support/education; n = 56), on the World Health Organization QoL BREF, Disability, and Autism-Specific scales in adults with ASD.

RESULTS

In Study 1, we replicated findings that mental HRQoL is worse in both men and women with ASD, compared to NT counterparts, but physical HRQoL is only worse in women with ASD. We present novel findings that older age is associated with better mental HRQoL in women with ASD only. In Study 2, MBSR improved disability-related QoL in adults with ASD over and above the support/education intervention, but both interventions improved mental HRQoL. Lastly, both interventions were more effective for HRQoL improvements in women with ASD.

CONCLUSION

Findings encourage precision medicine approaches tailored to age and sex groups for best HRQoL outcomes in adults with ASD.

CLINICALTRIALS

gov Identifier: NCT04017793.

IQ in Autism Spectrum Disorder: A Population-Based Birth Cohort Study

OBJECTIVES

We aimed to describe the intellectual ability and ratio of boys to girls with average or higher IQ within autism spectrum disorder (ASD) cases identified in a population-based birth cohort. We hypothesized that research-identified individuals with ASD would be more likely to have average or higher IQ, compared to clinically diagnosed ASD. We also hypothesized the male to female ratio would decrease as the definition of ASD broadened.

METHODS

ASD incident cases were identified from 31 220 subjects in a population-based birth cohort. Research-defined autism spectrum disorder, inclusive criteria (ASD-RI) was based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, autistic disorder (AD), Asperger Disorder, and pervasive developmental disorder not otherwise specified criteria. Research-defined autism spectrum disorder, narrow criteria (ASD-RN) was a narrower definition based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision AD criteria. Clinical diagnoses of ASD were abstracted from medical and school records. Intellectual ability was based on the last IQ score or on documented diagnoses of intellectual disability if no scores available. Average or higher IQ was defined as IQ ≥86.

RESULTS

A total of 59.1% of those with ASD-RI (n = 890), 51.2% of those with ASD-RN (n = 453), and 42.8% of those with clinically diagnosed autism spectrum disorder (n = 187) had average or higher IQ. Within the ASD-RI and ASD-RN groups, boys were more likely than girls to have an average or higher IQ (62.0% vs 51.3% [P = .004] and 54.1% vs. 42.5% [P = .03], respectively).

CONCLUSION

Our data suggest that nearly half of individuals with ASD have average or higher IQ. Boys with ASD are more likely to have average or higher IQ than girls. Patients with ASD and higher IQ remain at risk for not being identified.

Prevalence of epilepsy in autism spectrum disorders: A systematic review and meta-analysis

LAY ABSTRACT

Autistic individuals experience higher co-occurring medical conditions than the general population, and yet the estimates of autistic individuals with epilepsy are not updated. Co-occurrence of epilepsy in autistic individuals often aggravated cognitive impairment and increased the risk of poor long-term prognosis. Thus, an updated systematic review and meta-analysis was conducted to study the relevant articles published from inception to 2020, evaluate the prevalence of epilepsy in autistic individuals, and further explore the putative factors influencing the prevalence. A total of 66 studies from 53 articles were included in this study. The results showed that epilepsy is more common in autistic individuals than in the general population. The prevalence of epilepsy in autistic individuals in the clinical sample-based studies was higher than that in the population-based based cross-sectional or cohort studies. The prevalence of epilepsy in autistic adults was higher than that in autistic children. A significantly increased prevalence of epilepsy was detected in the autistic adolescent group (11-17 years old), and a higher trend of prevalence of epilepsy was observed in the autistic pre-school group (⩽ 6 -years-old) than that of the autistic school-aged group (7-10 years-old). The prevalence of epilepsy increased with age, female rate, and low intellectual function rate of autistic individuals. However, the human development index of countries was negatively associated with the pooled prevalence, which could be attributed to the different levels of awareness, diagnostic technologies, and autism-service support worldwide. About 1/10 autistic individuals also had epilepsy, which was common in the clinical setting, adolescents, adults, females, or patients with intellectual disability and less common in the country with high human development index. Thus, these findings provided critical and innovative views on the prevalence of epilepsy in autistic individuals and contributed to the targeted clinical management and preventive measures.

What is autism?

The term "Autism spectrum disorder" (ASD), in vogue at present, has evolved after continual substantial developments taking place over more than a century. ASD is a heterogeneous, multi-factorial, developmental disability in which an unusual pattern of development takes place during infant and toddler years. As per DSM-5, Autism spectrum disorder is a combined phrase for a family of complex developmental disabilities inclusive of "Autistic Disorder, Pervasive Developmental Disorder not Otherwise Specified (PDD-NOS), and Asperger's Disorder". "ASD is characterized not only by persistent impairments in reciprocal social communication and social interactions, but is also manifested by restricted, repetitive patterns of behavior, interests, or activities". The classical clinical signs that exist in two major domains, viz. the 'social domain' and the 'behavioral domain' for the precise diagnosis of ASD have been tabulated and major differences between DSM-5 and DSM-4 are depicted with the help of a figure in this basic review article. A sharp rise in the incidence of ASD cases has been observed worldwide owing to various risk factors such as genetic predisposition coupled with adverse environmental conditions, gynecological interventions, etc. Two official manuals viz. the "Diagnostic and Statistical Manual of Mental Disorders" (DSM) (published by the American Psychiatric Association), and the "International Classification of Diseases" (ICD) (published by the World Health Organization) is being regularly updated to facilitate diagnosis of ASD. ICD-11 guidelines being prospectively implemented with effect from January 2022 have attracted global attention.

Tracing Autism Traits in Large Multiplex Families to Identify Endophenotypes of the Broader Autism Phenotype

Families comprising many individuals with Autism Spectrum Disorders (ASD) may carry a dominant predisposing mutation. We implemented rigorous phenotyping of the "Broader Autism Phenotype" (BAP) in large multiplex ASD families using a novel endophenotype approach for the identification and characterisation of distinct BAP endophenotypes. We evaluated ASD/BAP features using standardised tests and a semi-structured interview to assess social, intellectual, executive and adaptive functioning in 110 individuals, including two large multiplex families (Family A: 30; Family B: 35) and an independent sample of small families (n = 45). Our protocol identified four distinct psychological endophenotypes of the BAP that were evident across these independent samples, and showed high sensitivity (97%) and specificity (82%) for individuals classified with the BAP. Patterns of inheritance of identified endophenotypes varied between the two large multiplex families, supporting their utility for identifying genes in ASD.

Epidemiology of Autism Spectrum Disorders: A Review of Worldwide Prevalence Estimates Since 2014

The prevalence of Autism Spectrum Disorder (ASD) has increased dramatically in recent decades, supporting the claim of an autism epidemic. Systematic monitoring of ASD allows estimating prevalence and identifying potential sources of variation over time and geographical areas. At present, ASD prevalence estimates are available worldwide, coming either from surveillance systems using existing health and educational databases or from population studies specifically performed. In the present article, we present a review of the ASD prevalence estimates published since 2014. Data confirm a high variability in prevalence across the world, likely due to methodological differences in case detection, and the consistent increase of prevalence estimates within each geographical area.

The state of research on the genetics of autism spectrum disorder: methodological, clinical and conceptual progress

Autism spectrum disorder (ASD) is a behaviorally heterogeneous disorder with a strong genetic component, as evidenced by decades of twin and family studies. In recent years, enhanced methods of genomic sequencing have revealed that structural variation and mutations to both coding and non-coding regions of single, candidate genes may account for more than 30% of ASD cases. The current review highlights a genotype-first approach that builds upon these molecular findings to parse the heterogeneity of ASD. Advantages of this approach include strong potential for precision medicine diagnosis and treatment, as well as opportunity to advance basic science research on neurodevelopmental disorders. Psychosocial benefits of identifying genetic subtypes of ASD have already been realized through social networking, comprehensive clinical phenotyping, and increased awareness among providers of rare genetic mutations.

What Is the Male-to-Female Ratio in Autism Spectrum Disorder? A Systematic Review and Meta-Analysis

OBJECTIVE

To derive the first systematically calculated estimate of the relative proportion of boys and girls with autism spectrum disorder (ASD) through a meta-analysis of prevalence studies conducted since the introduction of the DSM-IV and the International Classification of Diseases, Tenth Revision.

METHOD

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The Medline, Embase, and PsycINFO databases were searched, and study quality was rated using a risk-of-bias tool. Random-effects meta-analysis was used. The pooled outcome measurement was the male-to-female odds ratio (MFOR), namely the odds of being male in the group with ASD compared with the non-ASD group. In effect, this is the ASD male-to-female ratio, controlling for the male-to-female ratio among participants without ASD.

RESULTS

Fifty-four studies were analyzed, with 13,784,284 participants, of whom 53,712 had ASD (43,972 boys and 9,740 girls). The overall pooled MFOR was 4.20 (95% CI 3.84-4.60), but there was very substantial between-study variability (I² = 90.9%). High-quality studies had a lower MFOR (3.32; 95% CI 2.88-3.84). Studies that screened the general population to identify participants regardless of whether they already had an ASD diagnosis showed a lower MFOR (3.25; 95% CI 2.93-3.62) than studies that only ascertained participants with a pre-existing ASD diagnosis (MFOR 4.56; 95% CI 4.10-5.07).

CONCLUSION

Of children meeting criteria for ASD, the true male-to-female ratio is not 4:1, as is often assumed; rather, it is closer to 3:1. There appears to be a diagnostic gender bias, meaning that girls who meet criteria for ASD are at disproportionate risk of not receiving a clinical diagnosis.

Vision Research Literature May Not Represent the Full Intellectual Range of Autism Spectrum Disorder

Sensory, in particular visual processing is recognized as often perturbed in individuals with Autism Spectrum Disorder (ASD). However, in terms of the literature pertaining to visual processing, individuals in the normal intelligence range (IQ = 90-110) and above, are more frequently represented in study samples than individuals who score below normal in the borderline intellectual disability (ID) (IQ = 71-85) to ID (IQ < 70) ranges. This raises concerns as to whether or not current research is generalizable to a disorder that is often co-morbid with ID. Thus, the aim of this review is to better understand to what extent the current ASD visual processing literature is representative of the entire ASD population as either diagnosed or recognized under DSM-5. Our recalculation of ASD prevalence figures, using the criteria of DSM-5, indicates approximately 40% of the ASD population are likely to be ID although searching of the visual processing literature in ASD up to July 2016 showed that only 20% of papers included the ASD with-ID population. In the published literature, the mean IQ sampled was found to be 104, with about 80% of studies sampling from the 96-115 of the IQ range, highlighting the marked under-representation of the ID and borderline ID sections of the ASD population. We conclude that current understanding of visual processing and perception in ASD is not based on the mean IQ profile of the DSM-5 defined ASD population that now appears to lie within the borderline ID to ID range. Give the importance of the role of vision for the social and cognitive processing in ASD, we recommend accurately representing ASD via greater inclusion of individuals with IQ below 80, in future ASD research.

Head-to-Head Comparison of Aripiprazole and Risperidone in the Treatment of ADHD Symptoms in Children with Autistic Spectrum Disorder and ADHD: A Pilot, Open-Label, Randomized Controlled Study

BACKGROUND

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are frequently overlapping neurodevelopmental disorders. Individuals in whom the disorders are comorbid show more severe impairment because of deficits in the processing of social situations, adaptive functioning, and executive control than individuals with either disorder alone.

OBJECTIVE

This open-label pilot study aimed to evaluate and compare the efficacy and tolerability of risperidone and aripiprazole for treating ADHD symptoms in patients with both ASD and ADHD over the course of 24 weeks of treatment.

METHODS

Patients (n = 44) were randomly assigned to start treatment with risperidone (22 patients) or aripiprazole (22 patients). Children were evaluated before starting treatment (T0), and after 12 weeks (T1) and 24 weeks (T2) of treatment. At each visit, specific psychiatric clinical scales were administered to assess the efficacy of the two drugs.

RESULTS

The mean age was 8.4 ± 2.9 years in the aripiprazole group and 7.8 ± 2.3 years in the risperidone group. A total of 37 children (29 boys and 8 girls) completed the study (18 in the aripiprazole group and 19 in the risperidone group). Aripiprazole and risperidone appeared to have similar benefits in terms of efficacy and tolerability, although there were slight differences between the two drugs. Both groups showed a significant improvement in ADHD symptoms after 24 weeks of treatment (ADHD Rating Scale, Conners Parent Rating Scale-Hyperactivity, and Clinical Global Improvement-Severity Scale). No significant difference between the two drugs on any parameters at 24 weeks were found. Prolactin levels were decreased in the aripiprazole group. Both drugs were well tolerated, with no serious adverse events detected.

CONCLUSIONS

Our study confirms the efficacy of both aripiprazole and risperidone in ameliorating ADHD symptoms of children also presenting with ASD.

Prevalence of Autism Spectrum Disorders in Siblings of Indian Children With Autism Spectrum Disorders

This study determined the prevalence of autism spectrum disorders in 201 siblings of children with autism spectrum disorders. Siblings were screened using Modified Checklist for Autism in Toddlers and Social Responsiveness Scale, parent version. Screen-positive siblings were assessed using Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria. The risk of autism spectrum disorder in siblings was correlated with various familial and disease characteristics of the index case. Prevalence of autism spectrum disorder in siblings was 4.97%. There was a significant effect of the presence of aggressive behavior, externalizing problems and total problems in the proband, assessed using Childhood Behavior Checklist, and the young age of the father at conception on sibling risk of autism spectrum disorder. Results of our study are in line with previous studies reporting similar prevalence but have also brought up the association with behavioral problems as a possible risk factor. Siblings of children with autism spectrum disorder should be routinely screened, and genetic counseling for this increased risk should be explained to the family.

Identifying autism early: The Toddlers at Risk of Autism Clinic model

AIM

This paper describes the Toddlers at Risk of Autism Clinic (TRAC), which utilises the Social Attention and Communication Study (SACS) and/or Autism Detection in Early Childhood (ADEC) play-based assessments to facilitate the early diagnosis of autism.

METHODS

A retrospective audit was conducted of all 42 children assessed over a 3-year period in the TRAC. A semi-structured interview and play-based assessment (SACS and ADEC) were used to aid experienced clinicians in diagnosing autism. Intervention was recommended, and families were routinely followed up. Analysis was conducted on the tools used, the outcomes of assessment, diagnosis and stability of diagnosis on follow-up.

RESULTS

During this period, 35 boys and 7 girls were assessed, with a mean age of 25 months. The average waiting time for clinic was 11.6 weeks. Twenty-five patients were diagnosed with autism; 90.5% of toddlers given an initial diagnosis retained that diagnosis at follow-up. Out of the 17 children who were not diagnosed with autism in the TRAC, one child was later diagnosed with autism.

CONCLUSION

Experienced clinicians can use the SACS and/or ADEC to assist with a Diagnostic and Statistical Manual diagnosis of autism in toddlers.

Daytime physical activity and sleep in pre-schoolers with developmental disorders

AIM

This study aims to investigate the association between daytime physical activity (PA) and sleep in pre-schoolers with or without autism spectrum disorders (ASDs).

METHOD

Thirty-one pre-school children with ASD and 16 age-matched controls were recruited. Sleep and PA patterns were measured with an Actiwatch for 7 days. After average PA values were calculated for three periods (morning, afternoon and evening) of each day for each child, the days with maximum (active) and minimum (inactive) PA values for these three periods were determined. The Wilcoxon signed-rank test was used to compare sleep following active mornings, afternoons and evenings with that following inactive time periods.

RESULTS

In control children, sleep onset time following active mornings/afternoons did not differ from that following inactive mornings/afternoons. In contrast, sleep onset following the most inactive morning (median sleep onset time: 9:57 pm) and the most inactive afternoon (median sleep onset time: 10:24 pm) began significantly later than that following the most active mornings (median sleep onset time: 9:21 pm) and the most active afternoons (median sleep onset time: 9:39 pm) in children with ASD. The percentage of sleep for control children following active mornings was significantly higher (median: 93.2%) than that following inactive ones (median: 91.7%). Significant associations were not found between evening PA and sleep in either ASD or control children.

CONCLUSIONS

A high level of morning and afternoon PA can advance the sleep phase in children with ASD.

Genetic testing in children with autism spectrum disorders

OBJECTIVE

The aim of this study was to investigate karyotype abnormalities, MECP2 mutations, and Fragile X in a clinical population of children with Autism Spectrum Disorders (ASD) using The Clinical Report published by the American Academy of Pediatrics.

METHODS

Ninety-six children with ASD were evaluated for genetic testing and factors associated with this testing.

RESULTS

Abnormalities were found on karyotype in 9.7% and in DNA for fragile X in 1.4%. Karyotype abnormalities include inv(9)(p12q13); inv(9)(p11q13); inv(Y)(p11q11); Robertsonian translocation (13;14)(8q10q10) and (13,14)(q10q10); 9qh+; Yqh+; 15ps+; deletion 13(p11.2).

CONCLUSION

Genetic testing should be offered to all families of a child with an ASD, even not all of them would follow this recommendation. Although karyotype and FRAXA assessment will yield almost 10% positive results, a detailed history and physical examination are still the most important aspect of the etiological evaluation for children with ASD. Also, it is important to have geneticists to help in interpreting the information obtained from genetic testing.

Evidence for ASD recurrence rates and reproductive stoppage from large UK ASD research family databases

Following a diagnosis of a developmental disorder such as autism spectrum disorder (ASD) in early childhood, parents may decide to have fewer children than previously planned. The tendency for families to halt reproduction after receiving a diagnosis for one child is known as reproductive stoppage. Stoppage may lead to an underestimate of recurrence risk estimates of parents having more than one child with ASD. Using two large UK ASD family databases, we investigated recurrence rates for ASD and evidence for reproductive stoppage for both ASD and undiagnosed ASD/broader autism phenotype in a subgroup of families. Reproductive stoppage was tested for using the Mann-Whitney U-test to disprove the null hypothesis that affected and nonaffected children were distributed randomly by birth order. Dahlberg's later-sib method was used to estimate recurrence risk and take stoppage into account. Data were available from 299 families (660 children) including 327 with ASD. Ten percent of the complete families had more than one child with an ASD. Using Dahlberg's later-sib method, the recurrence risk for ASD was 24.7% overall and 50.0% in families with two or more older siblings with ASD. Children with ASD were born significantly later in families than those without ASD in all sibship combinations. This study shows strong evidence that ASD is associated with reproductive stoppage. These data have important implications for family planning and genetic counseling.

Advances in Genetic Discovery and Implications for Counseling of Patients and Families with Autism Spectrum Disorders

The prevalence of autism spectrum disorders (ASD) continues to increase. Genetic factors play an important role in the etiology of ASD, although specific genetic causes are identified in only a minority of cases. Recent advances have accelerated the discovery of genes implicated in ASD through convergent genomic analysis of genome-wide association studies, chromosomal microarray, exome sequencing, genome sequencing, and gene networks. Hundreds of candidate genes for ASD have been reported, yet only a handful have proven causative. Symptoms are complex and highly variable, and most cases are likely due to cumulative genetic factors, the interactions among them, as well as environmental factors. Here we summarize recent findings in genomic research regarding discovery of candidate genes, describe the major molecular processes in neural development that may be disrupted in ASD, and discuss the implication of research findings in clinical genetic diagnostic testing and counseling. Continued advances in genetic research will eventually translate into innovative approaches to prevention and treatment of ASD.

Clinical neurogenetics: autism spectrum disorders

Autism spectrum disorders are neurodevelopmental disorders characterized by deficits in social interactions, communication, and repetitive or restricted interests. There is strong evidence that de novo or inherited genetic alterations play a critical role in causing Autism Spectrum Disorders, but non-genetic causes, such as in utero infections, may also play a role. Magnetic resonance imaging based and autopsy studies indicate that early rapid increase in brain size during infancy could underlie the deficits in a large subset of subjects. Clinical studies show benefits for both behavioral and pharmacological treatment strategies. Genotype-specific treatments have the potential for improving outcome in the future.

A Danish population-based twin study on autism spectrum disorders

Genetic epidemiological studies of Autism Spectrum Disorders (ASDs) based on twin pairs ascertained from the population and thoroughly assessed to obtain a high degree of diagnostic validity are few. All twin pairs aged 3-14 years in the nationwide Danish Twin Registry were approached. A three-step procedure was used. Five items from the "Child Behaviour Checklist" (CBCL) were used in the first screening phase, while screening in the second phase included the "Social and Communication Questionnaire" and the "Autism Spectrum Screening Questionnaire". The final clinical assessment was based on "gold standard" diagnostic research procedures including diagnostic interview, observation and cognitive examination. Classification was based on DSM-IV-TR criteria. The initial sample included 7,296 same-sexed twin pairs and, after two phases of screening and clinical assessment, the final calculations were based on 36 pairs. The probandwise concordance rate for ASD was 95.2% in monozygotic (MZ) twins (n=13 pairs) and 4.3% in dizygotic (DZ) twins (n=23 pairs). The high MZ and low DZ concordance rate support a genetic aetiology to ASDs.

Shared and distinct intrinsic functional network centrality in autism and attention-deficit/hyperactivity disorder

BACKGROUND

Individuals with autism spectrum disorders (ASD) often exhibit symptoms of attention-deficit/hyperactivity disorder (ADHD). Across both disorders, observations of distributed functional abnormalities suggest aberrant large-scale brain network connectivity. Yet, common and distinct network correlates of ASD and ADHD remain unidentified. Here, we aimed to examine patterns of dysconnection in school-age children with ASD and ADHD and typically developing children who completed a resting state functional magnetic resonance imaging scan.

METHODS

We measured voxelwise network centrality, functional connectivity metrics indexing local (degree centrality [DC]) and global (eigenvector centrality) functional relationships across the entire brain connectome, in resting state functional magnetic resonance imaging data from 56 children with ASD, 45 children with ADHD, and 50 typically developing children. A one-way analysis of covariance, with group as fixed factor (whole-brain corrected), was followed by post hoc pairwise comparisons.

RESULTS

Cortical and subcortical areas exhibited centrality abnormalities, some common to both ADHD and ASD, such as in precuneus. Others were disorder-specific and included ADHD-related increases in DC in right striatum/pallidum, in contrast with ASD-related increases in bilateral temporolimbic areas. Secondary analyses differentiating children with ASD into those with or without ADHD-like comorbidity (ASD(+) and ASD(-), respectively) revealed that the ASD(+) group shared ADHD-specific abnormalities in basal ganglia. By contrast, centrality increases in temporolimbic areas characterized children with ASD regardless of ADHD-like comorbidity. At the cluster level, eigenvector centrality group patterns were similar to DC.

CONCLUSIONS

ADHD and ASD are neurodevelopmental disorders with distinct and overlapping clinical presentations. This work provides evidence for both shared and distinct underlying mechanisms at the large-scale network level.

Prenatal and perinatal analgesic exposure and autism: an ecological link

BACKGROUND

Autism and Autism Spectrum Disorder (ASD) are complex neurodevelopmental disorders. Susceptibility is believed to be the interaction of genetic heritability and environmental factors. The synchronous rises in autism/ASD prevalence and paracetamol (acetaminophen) use, as well as biologic plausibility have led to the hypothesis that paracetamol exposure may increase autism/ASD risk.

METHODS

To explore the relationship of antenatal paracetamol exposure to ASD, population weighted average autism prevalence rates and paracetamol usage rates were compared. To explore the relationship of early neonatal paracetamol exposure to autism/ASD, population weighted average male autism prevalence rates for all available countries and U.S. states were compared to male circumcision rates - a procedure for which paracetamol has been widely prescribed since the mid-1990s. Prevalence studies were extracted from the U.S. Centers for Disease Control and Prevention Summary of Autism/ASD Prevalence Studies database. Maternal paracetamol usage and circumcision rates were identified by searches on Pub Med.

RESULTS

Using all available country-level data (n = 8) for the period 1984 to 2005, prenatal use of paracetamol was correlated with autism/ASD prevalence (r = 0.80). For studies including boys born after 1995, there was a strong correlation between country-level (n = 9) autism/ASD prevalence in males and a country's circumcision rate (r = 0.98). A very similar pattern was seen among U.S. states and when comparing the 3 main racial/ethnic groups in the U.S. The country-level correlation between autism/ASD prevalence in males and paracetamol was considerably weaker before 1995 when the drug became widely used during circumcision.

CONCLUSIONS

This ecological analysis identified country-level correlations between indicators of prenatal and perinatal paracetamol exposure and autism/ASD. State level correlation was also identified for the indicator of perinatal paracetamol exposure and autism/ASD. Like all ecological analyses, these data cannot provide strong evidence of causality. However, biologic plausibility is provided by a growing body of experimental and clinical evidence linking paracetamol metabolism to pathways shown to be important in autism and related developmental abnormalities. Taken together, these ecological findings and mechanistic evidence suggest the need for formal study of the role of paracetamol in autism.

Clinical genetics evaluation in identifying the etiology of autism spectrum disorders: 2013 guideline revisions

The autism spectrum disorders are a collective of conditions that have in common impaired socialization and communication in association with stereotypic behaviors. The reported incidence of autism spectrum disorders has increased dramatically over the past two decades. In addition, increased attention has been paid to these conditions by both lay and professional groups. These trends have resulted in an increase in the number of referrals to clinical geneticist for the evaluation of persons with autism spectrum disorders. The primary roles of the geneticist in this process are to define etiology when possible, to provide genetic counseling, and to contribute to case management. In deciding on the appropriate evaluation for a particular patient, the geneticist will consider a host of factors: (i) ensuring an accurate diagnosis of autism before proceeding with any investigation; (ii) discussing testing options, diagnostic yields, and family investment before proceeding with an evaluation; (iii) communicating and coordinating with the patient-centered medical home (PCMH); (iv) assessing the continuously expanding and evolving list of available laboratory-testing modalities in light of the published literature; (v) recognizing the expanded phenotypes of well-described syndromic and metabolic conditions that overlap with autism spectrum disorders; and (vi) defining an individualized evaluation plan based on the unique history and clinical features of a given patient. The guidelines in this paper have been developed to assist the clinician in the consideration of these factors. It updates the original publication from 2008.Genet Med 2013:15(5):399-407.

The Study to Explore Early Development (SEED): a multisite epidemiologic study of autism by the Centers for Autism and Developmental Disabilities Research and Epidemiology (CADDRE) network

The Study to Explore Early Development (SEED), a multisite investigation addressing knowledge gaps in autism phenotype and etiology, aims to: (1) characterize the autism behavioral phenotype and associated developmental, medical, and behavioral conditions and (2) investigate genetic and environmental risks with emphasis on immunologic, hormonal, gastrointestinal, and sociodemographic characteristics. SEED uses a case-control design with population-based ascertainment of children aged 2-5 years with an autism spectrum disorder (ASD) and children in two control groups-one from the general population and one with non-ASD developmental problems. Data from parent-completed questionnaires, interviews, clinical evaluations, biospecimen sampling, and medical record abstraction focus on the prenatal and early postnatal periods. SEED is a valuable resource for testing hypotheses regarding ASD characteristics and causes.

Global prevalence of autism and other pervasive developmental disorders

We provide a systematic review of epidemiological surveys of autistic disorder and pervasive developmental disorders (PDDs) worldwide. A secondary aim was to consider the possible impact of geographic, cultural/ethnic, and socioeconomic factors on prevalence estimates and on clinical presentation of PDD. Based on the evidence reviewed, the median of prevalence estimates of autism spectrum disorders was 62/10 000. While existing estimates are variable, the evidence reviewed does not support differences in PDD prevalence by geographic region nor of a strong impact of ethnic/cultural or socioeconomic factors. However, power to detect such effects is seriously limited in existing data sets, particularly in low-income countries. While it is clear that prevalence estimates have increased over time and these vary in different neighboring and distant regions, these findings most likely represent broadening of the diagnostic concets, diagnostic switching from other developmental disabilities to PDD, service availability, and awareness of autistic spectrum disorders in both the lay and professional public. The lack of evidence from the majority of the world's population suggests a critical need for further research and capacity building in low- and middle-income countries.

Examining autistic traits in children with ADHD: does the autism spectrum extend to ADHD?

We examined to what extent increased parent reports of autistic traits in some children with Attention Deficit Hyperactivity Disorder (ADHD) are the result of ADHD-related symptoms or qualitatively similar to the core characteristics of autism spectrum disorders (ASD). Results confirm the presence of a subgroup of children with ADHD and elevated ratings of core ASD traits (ADHD(+)) not accounted for by ADHD or behavioral symptoms. Further, analyses revealed greater oppositional behaviors, but not greater ADHD severity or anxiety, in the ADHD(+) subgroup compared to those with ADHD only. These results highlight the importance of specifically examining autistic traits in children with ADHD for better characterization in studies of the underlying physiopathology and treatment.

Recurrence risk for autism spectrum disorders: a Baby Siblings Research Consortium study

OBJECTIVE

The recurrence risk of autism spectrum disorders (ASD) is estimated to be between 3% and 10%, but previous research was limited by small sample sizes and biases related to ascertainment, reporting, and stoppage factors. This study used prospective methods to obtain an updated estimate of sibling recurrence risk for ASD.

METHODS

A prospective longitudinal study of infants at risk for ASD was conducted by a multisite international network, the Baby Siblings Research Consortium. Infants (n = 664) with an older biological sibling with ASD were followed from early in life to 36 months, when they were classified as having or not having ASD. An ASD classification required surpassing the cutoff of the Autism Diagnostic Observation Schedule and receiving a clinical diagnosis from an expert clinician.

RESULTS

A total of 18.7% of the infants developed ASD. Infant gender and the presence of >1 older affected sibling were significant predictors of ASD outcome, and there was an almost threefold increase in risk for male subjects and an additional twofold increase in risk if there was >1 older affected sibling. The age of the infant at study enrollment, the gender and functioning level of the infant's older sibling, and other demographic factors did not predict ASD outcome.

CONCLUSIONS

The sibling recurrence rate of ASD is higher than suggested by previous estimates. The size of the current sample and prospective nature of data collection minimized many limitations of previous studies of sibling recurrence. Clinical implications, including genetic counseling, are discussed.

Neurological considerations: autism and Parkinson's disease

Within the spectrum of disorders that manifest obsessive-compulsive (OC) features lies a sub-cluster of neurological conditions. Autism and Parkinson's disease (PD) are examples of two such neurological disorders that seem quite dissimilar on the surface. Yet, both conditions can include repetitive behaviors of a compulsive-impulsive nature. Furthermore, while autism and PD differ in other associated symptom domains that shape the course of each disorder, both disorders share some phenomenology in the core domain of repetitive behaviors and involve basal ganglia and frontal lobe dysfunction, similar to OC disorder (OCD). Accordingly, examination of the similarities and differences between autism and PD may provide insight into the pathophysiology and treatment of OC spectrum disorders. The current review focuses on the phenomenology, comorbidity, course of illness, family history, brain circuitry, and treatment of autism and PD, as they relate to OCD and OC spectrum disturbances.

Epidemiology of pervasive developmental disorders

This article reviews the results of 43 studies published since 1966 that provided estimates for the prevalence of pervasive developmental disorders (PDDs), including autistic disorder, Asperger disorder, PDD not otherwise specified, and childhood disintegrative disorder. The prevalence of autistic disorder has increased in recent surveys and current estimates of prevalence are around 20/10,000, whereas the prevalence for PDD not otherwise specified is around 30/10,000 in recent surveys. Prevalence of Asperger disorder is much lower than that for autistic disorder and childhood disintegrative disorder is a very rare disorder with a prevalence of about 2/100,000. Combined all together, recent studies that have examined the whole spectrum of PDDs have consistently provided estimates in the 60-70/10,000 range, making PDD one of the most frequent childhood neurodevelopmental disorders. The meaning of the increase in prevalence in recent decades is reviewed. There is evidence that the broadening of the concept, the expansion of diagnostic criteria, the development of services, and improved awareness of the condition have played a major role in explaining this increase, although it cannot be ruled out that other factors might have also contributed to that trend.

What's new in autism?

This review on autism spectrum disorder (ASD) focusses on recent insights in the clinical picture, such as continuity of the phenotype and the concept of broader phenotype, on epidemiology and on clinical issues relevant to physicians, including new methods for early screening and diagnosis, psychiatric and somatic co-morbidity, and the expansion of so-called complementary and alternative treatments. ASD is a disorder with mainly genetic causes and recent insights show that a variety of genetic mechanisms may be involved, i.e. single gene disorders, copy number variations and polygenic mechanisms. Technological advances in genetics have lead to a number of promising findings, which, together with other lines of fundamental research, suggest that ASD may be a disorder of connectivity in the brain, at least in a subgroup of patients. It is possible that part of the genetic load in autism actually reflects gene-environment interaction, but there is no evidence for purely environmental causes in a substantial number of cases. Clinical research suggests that ASD may be a multi-system disorder in at least a subgroup of subjects, affecting the gastro-intestinal (GI) tract, the immune system and perhaps other systems. Behavioural treatments remain the cornerstone of management, and are mainly aimed at stimulation of the domains of impaired development and reducing secondary behaviours. These treatments are constantly being refined, but the main progress in this area may be the increase of research on effectiveness.

The prevalence of autism in Australia. Can it be established from existing data?

AIM

To assess whether existing data collection mechanisms can provide accurate and sufficient information about the prevalence of autism in Australia.

METHODS

Summary data about the number of children aged 0-16 years known to have an autism spectrum disorder (ASD) were gathered from State and Territory health, disability, education sources and autism associations. Summary data were also provided by national sources. Initial contact was made by letter, and follow-up was undertaken by telephone or email.

RESULTS

For the years 2003-2004, the estimated prevalence of autism for 6- to 12-year-olds ranged from 9.6 to 40.8/10 000 for the State and Territory data, and from 12.1 to 35.7/10 000 for the national data. There was a similar variation in prevalence estimates for children aged 0-5 and 13-16 years. There was also a variation in prevalence estimates between age groups.

CONCLUSION

Inconsistencies in autism prevalence estimates calculated from existing data sources suggest that further efforts are needed to ensure the collection of reliable information about the prevalence of ASD for national, State and Territory use. Existing data systems need to be improved or additional data systems need to be developed to ensure the collection of reliable information. Reliable and consistent ASD prevalence data would ensure that services are being provided to those who need them and would enhance the opportunities to undertake meaningful population-based research.

Epidemiological study of autism spectrum disorder in China

The object of this study was to investigate the epidemiologic pattern of autism spectrum disorder in Chinese children. An autism spectrum disorder registry has been established in Hong Kong since 1986 by collecting data in a single center (the only university-affiliated child assessment center in Hong Kong). Since 1997, inpatient data from all public hospitals under the Hospital Authority have been stored in a central computerized program and retrieved from the Clinical Data Analysis and Reporting System. Clinical data have also been retrieved through the Clinical Data Analysis and Reporting System to ensure the completion of the registry, and these suspected cases have undergone the same diagnostic evaluation for autism spectrum disorder, as some of the new autism cases might be hospitalized in the public hospital. The incidence and prevalence of autism spectrum disorder have been calculated for the period of 1986 to 2005 using the population statistics available in the government for children less than 15 years old in Hong Kong. This study has included 4 247 206 person-years from 1986 to 2005 for children less than 15 years old and 1 174 322 person-years for those less than 5 years old in Hong Kong. Altogether, 645 children 0 to 4 years old with diagnoses of autism spectrum disorder were identified from 1986 to 2005. The estimated incidence of autism spectrum disorder was 5.49 per 10 000. The prevalence was 16.1 per 10 000 for children less than 15 years old for the same period. The male to female ratio was 6.58:1. This is the first reported epidemiologic study of autism spectrum disorder in Chinese children. The incidence rate is similar to those reported in Australia and North America and is lower than Europeans.

A preliminary study on screening prevalence of pervasive developmental disorder in schoolchildren in Iran

To study prevalence rates of pervasive developmental disorder (PDD) symptoms and differences between subtypes in school age Iranian children. A random sample of 2,000 school age children from both genders was selected. A parent-completed, DSM-IV-referenced rating scale of PDD symptoms was used. About 1.9% of the sample obtained screening cutoff scores for probable autistic disorder and 0.5 for probable asperger's disorder. The rate of probable PDD was not more in girls than the boys. The rate of suspected cases of PDD in Iran is very high and probable autistic disorder is not gender related. It shows the need for more consideration of PDD in the mental health programs planning.

Validity of the Social Communication Questionnaire in Assessing Risk of Autism in Preschool Children with Developmental Problems

This study estimates the sensitivity and specificity of the social communication questionnaire (SCQ) for autistic spectrum disorders in preschool children at high risk for developmental problems referred to a tertiary centre and compares the predictions of the SCQ and the referrer. The SCQ was completed by 81 parents prior to multidisciplinary assessment and compared with the final diagnosis. The sensitivity and specificity were 93% and 58% for children aged 2-6, and 100 and 62% for children aged 3-5 years, with a cut-off score of 11. The SCQ performed better than referrers. Low-specificity means the SCQ is not suitable as a diagnostic tool but will assist clinicians and tertiary services in selecting children with developmental problems who require autism-specific assessment.

Sibling risk of pervasive developmental disorder estimated by means of an epidemiologic survey in Nagoya, Japan

Broad-spectrum autism, referred to as pervasive developmental disorder (PDD), may be associated with genetic factors. We examined 241 siblings in 269 Japanese families with affected children. The sibling incidence of PDD was 10.0% whereas the prevalence of PDD in the general population in the same geographic region was 2.1%. Both of these rates are higher than those reported previously, probably because of the expanded clinical criteria applied. The prevalence in males of the general population was 3.3% and that in females was 0.82%. The sibling incidences were 7.7 and 20.0% for families in which the probands were male and female, respectively. Because the reversed sex ratios correspond to the general rule for a multifactorial threshold model, we suggest that most PDD cases result from the cumulative effects of multiple factors (mostly genetic). The sibling incidences were 0 and 10.9% for families in which the proband had low and normal birth-weight, respectively, suggesting the risk is lower in families with low-birth-weight probands.

Incidence of autism spectrum disorders in children in two Australian states

AIM

To ascertain the incidence of autism spectrum disorders in Australian children.

SETTING

New South Wales (NSW) and Western Australia (WA), July 1999 to December 2000.

DESIGN

Data were obtained for WA from a prospective register and for NSW by active surveillance.

MAIN OUTCOME MEASURES

Newly recognised cases of autism spectrum disorders (defined as autistic disorder, Asperger disorder and pervasive developmental disorder not otherwise specified [PDD-NOS]) in children aged 0-14 years; incidence was estimated in 5-year age bands (0-4 years, 5-9 years, 10-14 years).

RESULTS

In WA, 252 children aged 0-14 years were identified with autism spectrum disorder (169 with autistic disorder and 83 with Asperger disorder or PDD-NOS). Comparable figures in NSW were 532, 400 and 132, respectively. Most children were recognised with autistic disorder before school age (median age, 4 years in WA and 3 years in NSW). Incidence of autistic disorder in the 0-4-years age group was 5.5 per 10,000 in WA (95% CI, 4.5-6.7) and 4.3 per 10,000 in NSW (95% CI, 3.8-4.8). Incidence was lower in older age groups. The ratio of all autism spectrum disorders to autistic disorder alone was 1.5:1 in WA and 1.3:1 in NSW, and rose with age (1.8:1 and 2.9:1 in 10-14-year-olds in WA and NSW, respectively).

CONCLUSIONS

These are the first reported incidence rates for autism for a large Australian population and are similar to rates reported from the United Kingdom. Ongoing information gathering in WA and repeat active surveillance in NSW will help to monitor any future changes.