How commonly are known medical conditions associated with autism?

Chemical Modulators for Targeting Autism Spectrum Disorders: From Bench to Clinic

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by diverse behavioral symptoms such as repetitive behaviors, social deficits, anxiety, hyperactivity, and irritability. Despite their increasing incidence, the specific pathological mechanisms of ASD are still unknown, and the degree and types of symptoms that vary from patient to patient make it difficult to develop drugs that target the core symptoms of ASD. Although various atypical antipsychotics and antidepressants have been applied to regulate ASD symptoms, these drugs can only alleviate the symptoms and do not target the major causes. Therefore, development of novel drugs targeting factors directly related to the onset of ASD is required. Among the various factors related to the onset of ASD, several chemical modulators to treat ASD, focused on serotonin (5-hydroxytryptamine, 5-HT) and glutamate receptors, microbial metabolites, and inflammatory cytokines, are explored in this study. In particular, we focus on the chemical drugs that have improved various aspects of ASD symptoms in animal models and in clinical trials for various ages of patients with ASD.

Health care providers' awareness on medical management of children with autism spectrum disorder: cross-sectional study in Russia

BACKGROUND

Autism spectrum disorder (ASD) is a complex developmental range of conditions that involves difficulties with social interaction and restricted/repetitive behaviors. Unfortunately, health care providers often experience difficulties in diagnosis and management of individuals with ASD, and may have no knowledge about possible ways to overcome barriers in ASD patient interactions in healthcare settings. At the same time, the provision of appropriate medical services can have positive effects on habilitative progress, functional outcome, life expectancy and quality of life for individuals with ASD.

METHODS

This online survey research study evaluated the awareness and experience of students/residents (n = 247) and physicians (n = 100) in the medical management of children with ASD. It also gathered the views and experiences of caregivers to children with ASD (n = 158), all based in Russia.

RESULTS

We have established that the Russian medical community has limited ASD knowledge among providers, and have suggested possible reasons for this. Based on results from online surveys completed by students/residents, non-psychiatric physicians, and caregivers of children diagnosed with ASD, the main problems pertaining to medical management of individuals with ASD were identified. Possible problem solving solutions within medical practice were proposed.

CONCLUSIONS

The results from this study should be considered when implementing measures to improve healthcare practices, and when developing models for effective medical management, due to start not only in Russia but also in a number of other countries.

The Role of MicroRNAs in Cerebellar Development and Autism Spectrum Disorder During Embryogenesis

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules with wide-ranging and subtle effects on protein production. Their activity during the development of the cerebellum provides a valuable exemplar of how non-coding molecules may assist the development and function of the central nervous system and drive neurodevelopmental disorders. Three distinct aspects of miRNA contribution to early cerebellar development will here be reviewed. Aspects are the establishment of the cerebellar anlage, the generation and maturation of at least two principal cell types of the developing cerebellar microcircuit, and the etiology and early progression of autism spectrum disorder. It will be argued here that the autism spectrum is an adept model to explore miRNA impact on the cognitive and affective processes that descend from the developing cerebellum.

Autism comes to the hospital: The experiences of patients with autism spectrum disorder, their parents and health-care providers at two Canadian paediatric hospitals

Youth with autism spectrum disorder are a vulnerable, often poorly understood patient group, who may experience periodic and chronic health challenges, in addition to their primary developmental social and communication problems. Developmental and behavioural challenges can complicate management of acute health-care needs. To date, there is an absence of empirical research exploring the hospital experiences of children and youth with autism spectrum disorder, their families and their health-care providers. Therefore, the purpose of this study was to understand these experiences in order to inform hospital-based care. A total of 42 participants were interviewed (youth with autism spectrum disorder, their parents and health-care providers) at one of two Canadian paediatric hospitals, representing 20 distinct cases of patients with autism spectrum disorder. Results from the qualitative analyses indicated that patients with autism spectrum disorder faced several challenges in the context of health-care delivery in the hospital setting, as did their families and health-care provider team. Problems identified included communication and sensory challenges, and the degree of flexibility of health-care providers and the hospital organization. Supportive health-care providers were those who acknowledged parents as experts, inquired about the requirements of patients with autism spectrum disorder and implemented strategies that accommodated the unique clinical presentation of the individual patient. These recommendations have wide-reaching utility for hospital and health-care practices involving this patient group.

New directions in the treatment of autism spectrum disorders from animal model research

INTRODUCTION

Currently, there is not an effective pharmacotherapy for the core symptoms of the autism spectrum disorders (ASD), which include aberrant social behavior, delayed communication and repetitive behavior and/or restricted interests. There are several drugs that treat the symptoms associated with autism including irritability, aggressiveness and hyperactivity. Current drug research is based on the ongoing genetic, animal model and neuropathologic research. Two areas in particular, the glutamate and oxytocin systems, provide exciting new avenues for drug discovery.

AREAS COVERED

This review examines what approaches have been used for the drugs that are currently being used to treat people with ASD. For the most part, drugs that treat other neuropsychiatric disorders have been examined to treat the people with ASD, unfortunately with little effect on the core symptoms.

EXPERT OPINION

Until recently, there was not a plethora of knowledge about the neurobiological substrates of social behavior, pragmatic language usage and repetitive and/or restricted behaviors. Therefore, drug discovery has used the tools available for other neuropsychiatric disorders. Now that more biological information is available, there are many avenues for research for drug targets for ASD.

Diagnostic yield of genetic testing in children diagnosed with autism spectrum disorders at a regional referral center

The aim was to systematically review genetic testing guidelines in the evaluation of children with autism spectrum disorders (ASDs). The Clinical Report published by the American Academy of Pediatrics (AAP)(1) recommended individualizing the workup, including karyotype and specific DNA testing for fragile X syndrome. A recent publication reported higher rates of abnormalities on CGH microarray (CMA) testing on children with ASD.(2) The medical records of 507 children seen through the Kirch Developmental Services Center were abstracted for genetic testing and factors associated with this testing. Abnormalities were found on karyotype in 2.3% and in DNA for fragile X in 0.04%. The author concludes that the diagnostic yield of the genetic testing was low in this population. Furthermore, their findings support the theory that CMA can be considered as part of the initial genetic screening in children with ASD in most situations. Future studies will need to be done prospectively to evaluate children in a standard fashion.

Autism spectrum disorders

Pervasive developmental disorders are a group of neurodevelopmental disorders characterized by impairments in communication, reciprocal social interaction and restricted repetitive behaviors or interests. The term autism spectrum disorders (ASD) has been used to describe their variable presentation. Although the cause of these disorders is not yet known, studies strongly suggest a genetic basis with a complex mode of inheritance. More research is needed to explore environmental factors that could be contributing to the cause of these disorders. The occurrence of ASD has been increasing worldwide, with the most recent prevalence studies indicating that they are present in 6 per 1000 children. The objectives of this article are to provide physicians with relevant information needed to identify and refer children presenting with symptoms suggestive of ASDs to specialized centers early, and to make them feel comfortable in dealing with public concerns regarding controversial issues about the etiology and management of these disorders.

Investigation of post-transcriptional gene regulatory networks associated with autism spectrum disorders by microRNA expression profiling of lymphoblastoid cell lines

Background

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by abnormalities in reciprocal social interactions and language development and/or usage, and by restricted interests and repetitive behaviors. Differential gene expression of neurologically relevant genes in lymphoblastoid cell lines from monozygotic twins discordant in diagnosis or severity of autism suggested that epigenetic factors such as DNA methylation or microRNAs (miRNAs) may be involved in ASD.

Methods

Global miRNA expression profiling using lymphoblasts derived from these autistic twins and unaffected sibling controls was therefore performed using high-throughput miRNA microarray analysis. Selected differentially expressed miRNAs were confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis, and the putative target genes of two of the confirmed miRNA were validated by knockdown and overexpression of the respective miRNAs.

Results

Differentially expressed miRNAs were found to target genes highly involved in neurological functions and disorders in addition to genes involved in gastrointestinal diseases, circadian rhythm signaling, as well as steroid hormone metabolism and receptor signaling. Novel network analyses of the putative target genes that were inversely expressed relative to the relevant miRNA in these same samples further revealed an association with ASD and other co-morbid disorders, including muscle and gastrointestinal diseases, as well as with biological functions implicated in ASD, such as memory and synaptic plasticity. Putative gene targets (ID3 and PLK2) of two RT-PCR-confirmed brain-specific miRNAs (hsa-miR-29b and hsa-miR-219-5p) were validated by miRNA overexpression or knockdown assays, respectively. Comparisons of these mRNA and miRNA expression levels between discordant twins and between case-control sib pairs show an inverse relationship, further suggesting that ID3 and PLK2 are in vivo targets of the respective miRNA. Interestingly, the up-regulation of miR-23a and down-regulation of miR-106b in this study reflected miRNA changes previously reported in post-mortem autistic cerebellum by Abu-Elneel et al. in 2008. This finding validates these differentially expressed miRNAs in neurological tissue from a different cohort as well as supports the use of the lymphoblasts as a surrogate to study miRNA expression in ASD.

Conclusions

Findings from this study strongly suggest that dysregulation of miRNA expression contributes to the observed alterations in gene expression and, in turn, may lead to the pathophysiological conditions underlying autism.

What causes autism? Exploring the environmental contribution

PURPOSE OF REVIEW

Autism is a biologically based disorder of brain development. Genetic factors--mutations, deletions, and copy number variants--are clearly implicated in causation of autism. However, they account for only a small fraction of cases, and do not easily explain key clinical and epidemiological features. This suggests that early environmental exposures also contribute. This review explores this hypothesis.

RECENT FINDINGS

Indirect evidence for an environmental contribution to autism comes from studies demonstrating the sensitivity of the developing brain to external exposures such as lead, ethyl alcohol and methyl mercury. But the most powerful proof-of-concept evidence derives from studies specifically linking autism to exposures in early pregnancy - thalidomide, misoprostol, and valproic acid; maternal rubella infection; and the organophosphate insecticide, chlorpyrifos. There is no credible evidence that vaccines cause autism.

SUMMARY

Expanded research is needed into environmental causation of autism. Children today are surrounded by thousands of synthetic chemicals. Two hundred of them are neurotoxic in adult humans, and 1000 more in laboratory models. Yet fewer than 20% of high-volume chemicals have been tested for neurodevelopmental toxicity. I propose a targeted discovery strategy focused on suspect chemicals, which combines expanded toxicological screening, neurobiological research and prospective epidemiological studies.

Limitations in life participation and independence due to secondary conditions

The effects of secondary conditions across adults with autism, Down syndrome, and cerebral palsy were explored in terms of overall limitation in life participation and independence, changes over time, and the degree and nature of limitation in specific secondary conditions. Information was obtained for 35 adults with autism, 49 with Down syndrome, and 29 with cerebral palsy (N = 113). Caregivers completed a questionnaire exploring secondary conditions on two occasions. Participants with cerebral palsy experienced the greatest overall limitations of the three groups. This finding is due to several secondary conditions. There were no changes in limitation scores over time. Implications related to health care for these groups are discussed.

Autism and Asperger's Syndrome

Autism and Asperger's syndrome are part of a range of conditions incorporated under the term autistic spectrum disorders (ASDs). This article will aim to define these conditions and explain the differences between them, clarify some of the myths about their aetiology and equip the reader with the specific knowledge to diagnose, refer and manage patients with ASDs as effectively as possible.

Medical conditions in autism spectrum disorders

Autism spectrum disorder (ASD) is a behaviourally defined syndrome where the etiology and pathophysiology is only partially understood. In a small proportion of children with the condition, a specific medical disorder is identified, but the causal significance in many instances is unclear. Currently, the medical conditions that are best established as probable causes of ASD include Fragile X syndrome, Tuberous Sclerosis and abnormalities of chromosome 15 involving the 15q11-13 region. Various other single gene mutations, genetic syndromes, chromosomal abnormalities and rare de novo copy number variants have been reported as being possibly implicated in etiology, as have several ante and post natal exposures and complications. However, in most instances the evidence base for an association with ASD is very limited and largely derives from case reports or findings from small, highly selected and uncontrolled case series. Not only therefore, is there uncertainty over whether the condition is associated, but the potential basis for the association is very poorly understood. In some cases the medical condition may be a consequence of autism or simply represent an associated feature deriving from an underlying shared etiology. Nevertheless, it is clear that in a growing proportion of individuals potentially causal medical conditions are being identified and clarification of their role in etio-pathogenesis is necessary. Indeed, investigations into the causal mechanisms underlying the association between conditions such as tuberous sclerosis, Fragile X and chromosome 15 abnormalities are beginning to cast light on the molecular and neurobiological pathways involved in the pathophysiology of ASD. It is evident therefore, that much can be learnt from the study of probably causal medical disorders as they represent simpler and more tractable model systems in which to investigate causal mechanisms. Recent advances in genetics, molecular and systems biology and neuroscience now mean that there are unparalleled opportunities to test causal hypotheses and gain fundamental insights into the nature of autism and its development.

Multiple rare variants in the etiology of autism spectrum disorders

Recent studies in autism spectrum disorders (ASDs) support an important role for multiple rare variants in these conditions. This is a clinically important finding, as, with the demonstration that a significant proportion of ASDs are the result of rare, etiological genetic variants, it becomes possible to make use of genetic testing to supplement behavioral analyses for an earlier diagnosis. As it appears that earlier interventions in ASDs will produce better outcomes, the development of genetic testing to augment behaviorally based evaluations in ASDs holds promise for improved treatment. Furthermore, these rare variants involve synaptic and neuronal genes that implicate specific paihvi/ays, cells, and subcellular compartments in ASDs, which in turn will suggest novel therapeutic approaches in ASDs, Of particular recent interest are the synaptic cell adhesion and associated molecules, including neurexin 1, neuroligin 3 and 4, and SHANK3, which implicate glutamatergic synapse abnormalities in ASDs, In the current review we will overview the evidence for a genetic etiology for ASDs, and summarize recent genetic findings in these disorders.

Fragile x syndrome and autism: from disease model to therapeutic targets

Autism is an umbrella diagnosis with several different etiologies. Fragile X syndrome (FXS), one of the first identified and leading causes of autism, has been modeled in mice using molecular genetic manipulation. These Fmr1 knockout mice have recently been used to identify a new putative therapeutic target, the metabotropic glutamate receptor 5 (mGluR5), for the treatment of FXS. Moreover, mGluR5 signaling cascades interact with a number of synaptic proteins, many of which have been implicated in autism, raising the possibility that therapeutic targets identified for FXS may have efficacy in treating multiple other causes of autism.

Parents' reports predict abnormal investigations in global developmental delay

AIMS

To identify symptoms reported by parents that predict abnormal laboratory investigations in preschoolers with global developmental delay (GDD).

METHODS

A cross-sectional descriptive study of 81 boys and 38 girls, with a mean age of 43.5 months (SD = 13.4), with global developmental delay. All parents/guardians completed the following: (1) a semistructured interview about their child and family; (2) the Child Development Inventory (CDI); (3) the Possible Problems Checklist (PPC); and (4) the Child Behavior Checklist 1(1/2)-5 (CBCL).

RESULTS

There were 61 abnormal results: MRI 37 (31%); high-resolution chromosomes 8 (7%); fragile X molecular testing 4 (3%); and microarray comparative genomic hybridization 12 (10%). A total of 47 children had abnormal tests (40%): none, 72 (60%); one, 36 (30%); two, 8 (7%); three, (3%). Younger children with more developmental delays are more likely to have abnormal tests. They are clumsy, more passive, and less disobedience. They had lower total, externalizing, and internalizing problems scores. The odds of finding an abnormal investigation are increasingly greater as parent's report of language comprehension and social development ratios increase, and decrease in likelihood for every increase in the expressive language and fine motor ratios.

INTERPRETATION

Parent's reports predict abnormal tests and indicate quantifiable differences requiring investigation.

Pervasive developmental disorders in individuals with cerebral palsy

The aim of the present study was to describe the prevalence and associated factors of pervasive developmental disorders (PDD), including autistic disorder and PDD not otherwise specified (NOS), in a clinical sample of 126 children and adolescents (75 males, 51 females; age range 4-18y, mean 8y 8mo, SD 3y 8mo) with tetraplegic, hemiplegic, diplegic, dyskinetic, or mixed types of cerebral palsy (CP); 28% could not crawl or walk even with support, 29% could move with support, and 43% walked independently. Participants were examined for PDD in two stages. In the first stage, probable participants were determined by direct observation, Autism Behavior Checklist score, and medical reports. In the second stage, those with 'probable' symptoms underwent psychiatric examination and their autistic symptoms were scored on the Childhood Autism Rating Scale. The final diagnosis of autistic disorder or PDD-NOS was given according to DSM-IV criteria. Fourteen (11%) and five (4%) of the participants met the criteria for autistic disorder and PDD-NOS respectively. Children with CP and PDD differed from those without PDD in terms of type of CP (p=0.02), presence of epilepsy (p<0.001), intellectual level (p<0.001), and level of speech (p<0.001). PDD was more common in children with tetraplegic, mixed, and hemiplegic CP, and in children with epilepsy, learning disability, and low level of speech. The findings corroborate the notion that CP is a complex disorder, often associated with additional impairments. PDD is not rare in CP and should be considered in patients with comorbid conditions such as epilepsy, learning disability, and language delay and in the presence of tetraplegic, mixed, and hemiplegic CP types.

Oculo-auriculo-vertebral spectrum: associated anomalies, functional deficits and possible developmental risk factors

Swedish patients with the oculo-auriculo-vertebral (OAV) spectrum participated in a prospective multidisciplinary investigation. The aims of the study were to describe their systemic and functional defects, especially autism spectrum disorders, and to search for possible etiologic risk factors. Available medical records were studied and the mothers answered a questionnaire on history of prenatal events. A clinical examination evaluating systemic findings, vision, hearing, speech, oral and swallowing function, and neuropsychiatric function, especially autism, was made. Eighteen patients, (11 males, 7 females) aged 8 months to 17 years with OAV were studied. Most frequent systemic malformations included, ear abnormalities (100%), ocular malformations (72%), vertebral deformities (67%), cerebral anomalies (50%), and congenital heart defects (33%). Functional defects consisted of hearing impairment (83%), visual impairment (28%), both visual and hearing impairment (28%), difficulties in feeding/eating (50%), speech (53%), mental retardation (39%), and severe autistic symptoms (11%). Three children were born following assisted fertilization (two intracytoplasmatic sperm injection, one in vitro fertilization), two mothers reported early bleedings, and six (33%) mothers had smoked during pregnancy.

Advances in behavioral genetics: mouse models of autism

Autism is a neurodevelopmental syndrome with markedly high heritability. The diagnostic indicators of autism are core behavioral symptoms, rather than definitive neuropathological markers. Etiology is thought to involve complex, multigenic interactions and possible environmental contributions. In this review, we focus on genetic pathways with multiple members represented in autism candidate gene lists. Many of these pathways can also be impinged upon by environmental risk factors associated with the disorder. The mouse model system provides a method to experimentally manipulate candidate genes for autism susceptibility, and to use environmental challenges to drive aberrant gene expression and cell pathology early in development. Mouse models for fragile X syndrome, Rett syndrome and other disorders associated with autistic-like behavior have elucidated neuropathology that might underlie the autism phenotype, including abnormalities in synaptic plasticity. Mouse models have also been used to investigate the effects of alterations in signaling pathways on neuronal migration, neurotransmission and brain anatomy, relevant to findings in autistic populations. Advances have included the evaluation of mouse models with behavioral assays designed to reflect disease symptoms, including impaired social interaction, communication deficits and repetitive behaviors, and the symptom onset during the neonatal period. Research focusing on the effect of gene-by-gene interactions or genetic susceptibility to detrimental environmental challenges may further understanding of the complex etiology for autism.

Identification and evaluation of children with autism spectrum disorders

Autism spectrum disorders are not rare; many primary care pediatricians care for several children with autism spectrum disorders. Pediatricians play an important role in early recognition of autism spectrum disorders, because they usually are the first point of contact for parents. Parents are now much more aware of the early signs of autism spectrum disorders because of frequent coverage in the media; if their child demonstrates any of the published signs, they will most likely raise their concerns to their child's pediatrician. It is important that pediatricians be able to recognize the signs and symptoms of autism spectrum disorders and have a strategy for assessing them systematically. Pediatricians also must be aware of local resources that can assist in making a definitive diagnosis of, and in managing, autism spectrum disorders. The pediatrician must be familiar with developmental, educational, and community resources as well as medical subspecialty clinics. This clinical report is 1 of 2 documents that replace the original American Academy of Pediatrics policy statement and technical report published in 2001. This report addresses background information, including definition, history, epidemiology, diagnostic criteria, early signs, neuropathologic aspects, and etiologic possibilities in autism spectrum disorders. In addition, this report provides an algorithm to help the pediatrician develop a strategy for early identification of children with autism spectrum disorders. The accompanying clinical report addresses the management of children with autism spectrum disorders and follows this report on page 1162 [available at www.pediatrics.org/cgi/content/full/120/5/1162]. Both clinical reports are complemented by the toolkit titled "Autism: Caring for Children With Autism Spectrum Disorders: A Resource Toolkit for Clinicians," which contains screening and surveillance tools, practical forms, tables, and parent handouts to assist the pediatrician in the identification, evaluation, and management of autism spectrum disorders in children.

Autism spectrum disorders in children with a history of infantile spasms: a population-based study

The objective of this article is to describe autistic spectrum disorders in children diagnosed with infantile spasms in the first year of life. The source of data was the records of all 3 pediatric departments in Iceland. Twenty children born between 1981 and 1998 who had infantile spasms were invited to participate. When appropriate, the parents of these children were asked to complete the Social Communication Questionnaire. Children scoring 10 points or higher on the questionnaire were selected for further examination using the Autism Diagnostic Interview- Revised and either the Autism Diagnostic Observation Schedule or the Childhood Autism Rating Scale. All participants were given appropriate cognitive tests or measures of adaptive behavior. The parents of 17 children (10 boys, 7 girls) agreed to participate in the study. Age at assessment ranged from 5 to 19 years with a mean age of 11 years and 6 months. Fourteen children had at least one neurodevelopmental disorder. Six (6/17), or 35.3%, were diagnosed with autism spectrum disorder (3 boys, 3 girls), five of these had a history of symptomatic infantile spasms, and four were profoundly mentally retarded (IQ/DQ<20). If the diagnosis of autism spectrum disorder was restricted to children with a developmental age of 24 months or more (3 cases), the prevalence was 17.6%. The estimates found in this study exceed the estimated prevalence of autism spectrum disorder in the general population.

Autism Spectrum Disorders in Children with Seizures in the First Year of Life-A Population-Based Study

PURPOSE

To describe autistic spectrum disorders (ASDs) in a cohort of children with history of unprovoked seizures other than infantile spasms in the first year of life.

METHODS

The source of data was computer records from all the three pediatric departments in Iceland. Children diagnosed 1982-2000 with unprovoked seizures with onset between 28 days and 12 months of age (N = 102) were invited to participate in a study. Children with known developmental disorders and those whose parents had concerns regarding their child's development or behavior were investigated for possible ASD. Parents were asked to complete the Social Communication Questionnaire and children scoring 10 points or higher were further examined with the Autism Diagnostic Interview-Revised and observational measures.

RESULTS

Eighty-four children (82.4%), 28 boys and 56 girls, participated in the study and 36.9% (31/84) were investigated for possible ASD. Twenty-four (28.6%) had at least one neurodevelopmental disorder, 14.3% had mental retardation (MR), and six (7.1%) were diagnosed with ASD, all of whom also had MR and three of whom had congenital brain abnormalities.

CONCLUSION

These results suggest that the estimated prevalence of ASD is higher in children with history of seizure in the first year of life than it is in the general population. There are indications that support the view that children with ASD and history of seizure in the first year of life have higher prevalence of congenital brain abnormalities and are more often female, than other children with ASD.

The autism epidemic: fact or artifact?

OBJECTIVE

We provide an illustration of how changes in methodological factors may produce variations in the frequency of autistic disorder (AD) over time and project how much of the observed increase in the frequency of AD may be explained by methodological factors.

METHOD

Using a prediction analysis, we calculate how broadening diagnostic criteria, younger age at diagnosis, and improved efficiency of case ascertainment could produce temporal trends in the incidence and prevalence of AD, measured by calendar year and by year of birth, in a hypothetical population of children 0 to 18 across the years 1950 to 2020.

RESULTS

Time trend studies report an increase as large as 11.0-fold over a 13-year period for AD. Conservative changes in the three methodological factors produced increases in the frequency of AD ranging from 2.1- to 28.8-fold. Measures of frequency by year of birth show the largest magnitude of increase; predicted prevalence by calendar year and to age 4 by year of birth are influenced by changes in the distribution of age at diagnosis, but 1-year incidence and prevalence to age 12 are not.

DISCUSSION

Methodological factors may explain the observed increases in AD over time. To increase confidence in reports of time trends, we recommend particular frequency measures and study circumstances.

Autism spectrum disorder and underlying brain mechanism in the oculoauriculovertebral spectrum

As part of a multidisciplinary study, the rate of autism spectrum disorder (ASD), learning disability (LD), and brain abnormalities was examined in 20 participants (12 males, 8 females; age range 8mo-17y, mean age 8y 1mo) diagnosed as falling within the oculoauriculovertebral spectrum (OAV). A neuropsychiatric examination was performed, including standardized autism diagnostic interviews. Two individuals met diagnostic criteria for autism, one for autistic-like condition, and five for autistic traits. Four patients had mild LD, three severe LD, two profound LD, and two borderline intellectual functioning. Neuroimaging indicated cerebral abnormalities in more than half of the patients. Abnormalities of white/grey matter were found in more than half of examined individuals; enlargement of ventricles in more than a third. Results indicate that at least a subgroup of ASD may be associated with errors in early embryonic brain development. Awareness of the coexistence of OAV/ASD is important in habilitation care of individuals with OAV.

Relationship of dietary intake to gastrointestinal symptoms in children with autistic spectrum disorders

BACKGROUND

Gastrointestinal (GI) symptoms and abnormalities in stool consistency are frequently reported by parents of children with autism spectrum disorders (ASD). The purpose of this study was to 1) describe dietary intake of a cohort of children with ASD compared with normative data and 2) determine whether GI symptoms and stool consistency are related to dietary intake.

METHODS

Data from diet diaries of children (3-8 years) with ASD (n = 62) were analyzed by a registered pediatric dietician to compare to RDA standards for total calories, protein, carbohydrate, and fat. Dietary intake was correlated with descriptors of stool consistency using cumulative logistic regression methods.

RESULTS

Intake of calories, carbohydrates, and fat were in the average range; protein intake was increased (211% of RDA). Reported frequency of GI abnormalities, including abnormal stool consistency (e.g., bulky or loose), was increased (54%). No statistically significant relationships between stool consistency and dietary intake were observed.

CONCLUSIONS

In this sample, there was a high rate of reported gastrointestinal symptoms, despite lack of medical causes. Intake was adequate for calories and carbohydrates and increased for protein. The children did not exhibit excessive carbohydrate intake. There was no association of nutrient intake to changes in stool consistency.

Identification and characterization of the TRIP8 and REEP3 genes on chromosome 10q21.3 as novel candidate genes for autism

Autism is a genetic neurodevelopmental disorder of unknown cause and pathogenesis. The identification of genes involved in autism is expected to increase our understanding of its pathogenesis. Infrequently, neurodevelopmental disorders like autism are associated with chromosomal anomalies. To identify candidate genes for autism, we initiated a positional cloning strategy starting from individuals with idiopathic autism carrying a de novo chromosomal anomaly. We report on the clinical, cytogenetic and molecular findings in a male person with autism, no physical abnormalities and normal IQ, carrying a de novo balanced paracentric inversion 46,XY,inv(10)(q11.1;q21.3). The distal breakpoint disrupts the TRIP8 gene, which codes for a protein predicted to be a transcriptional regulator associated with nuclear thyroid hormone receptors. However, no link between thyroid gland and autism has been reported so far. In addition, the same breakpoint abolishes expression of a nearby gene, REEP3, through a position effect. Receptor Expression-Enhancing Proteins (REEP) 3 is one of the six human homologs of yeast Yop1p, a probable regulator of cellular vesicle trafficking between the endoplasmatic reticulum and the Golgi network. These observations suggest that TRIP8 and REEP3 are both positional candidate genes for autism. In addition, our data indicate that in the selection of positional candidate genes when studying chromosomal aberrations, position effects should be taken into account.

Follow-up of children diagnosed with pervasive developmental disorders: stability and change during the preschool years

Forty-one children with pervasive developmental disorders (PDDs) receiving eclectic services were assessed twice during their preschool years. Measures were compared over time for the whole group and for diagnostic subgroups: Childhood autism (CA group) and Other PDDs group. The mean intelligence quotient/developmental quotient (IQ/DQ) of the whole group was stable (P = 0.209) and scores on the Childhood Autism Rating Scale (CARS) decreased (P = 0.001). At time 2, the CA group was more impaired than the other PDDs group: autistic symptoms were more severe (P = 0.01), adaptive behavior scores were lower (P = 0.014), and a trend for lower IQ/DQs (P = 0.06). Children in this study seemed to fare better than reported in previous follow-up studies on children with autism.

Medical investigation of children with autistic spectrum disorders

Few well-constructed studies have systematically evaluated medical investigation protocols for children with autistic spectrum disorders. This is in large part due to the heterogeneous nature of the population and changing diagnostic frameworks. This review outlines the studies that have directed investigation strategies to date, and discusses how these might be applied in the clinical situation. The importance of listing the conditions that may be present on the basis of the specific clinical presentation, and using a thorough history and examination to generate a pre-test probability of the target disorders is emphasized if tests are to be useful in directing therapy or broader management approaches.

Mouse models of autism spectrum disorders: The challenge for behavioral genetics

Autism is a severe neurodevelopmental disorder, which typically emerges early in childhood. The core symptoms of autism include deficits in social interaction, impaired communication, and aberrant repetitive behavior, including self-injury. Despite the strong genetic component for the disease, most cases of autism have not been linked to mutations in a specific gene, and the etiology of the disorder has yet to be established. At the present time, there is no generally accepted therapeutic strategy to treat the core symptoms of autism, and there remains a critical need for appropriate animal models and relevant behavioral assays to promote the understanding and treatment of the clinical syndrome. Challenges for the development of valid mouse models include complex genetic interactions underlying the high heritability of the disease in humans, diagnosis based on deficits in social interaction and communication, and the lack of confirmatory neuropathological markers to provide validation for genetic models of the disorder. Research focusing on genes that mediate social behavior in mice may help identify neural circuitry essential for normal social interaction, and lead to novel genetic animal models of the autism behavioral phenotype.

Array-based comparative genomic hybridization analysis of recurrent chromosome 15q rearrangements

Genomic rearrangements of chromosome 15q11-q13 cause diverse phenotypes including autism, Prader-Willi syndrome (PWS), and Angelman syndrome (AS). This region is subject to genomic imprinting and characterized by complex combinations of low copy repeat elements. Prader-Willi and Angelman syndrome are caused primarily by 15q11-13 deletions of paternal and maternal origin, respectively. Autism is seen with maternal, but not paternal, interstitial duplications. Isodicentric 15q, most often of maternal origin, is associated with a complex phenotype often including autistic features. Limitations of conventional cytogenetic tests preclude a detailed analysis in most patients with 15q rearrangements. We have developed a microarray for comparative genomic hybridization utilizing 106 genomic clones from chromosome 15q to characterize this region. The array accurately localized all breakpoints associated with gains or losses on 15q. The results confirmed the location of the common breakpoints associated with interstitial deletions and duplications. The majority of idic(15q) chromosomes are comprised of symmetrical arms with four copies of the breakpoint 1 to breakpoint 5 region. Patients with less common breakpoints that are not distinguished by routine cytogenetic methods were more accurately characterized by array analysis. This microarray provides a detailed characterization for chromosomal abnormalities involving 15q11-q14 and is useful for more precise genotype-phenotype correlations for autism, PWS, AS, and idic(15) syndrome.

Joubert syndrome is not a cause of classical autism

A previous report noted a 27% prevalence of autism in Joubert syndrome (JS), raising the question of overlapping etiologies. Family studies have shown that autism is characterized by family loading for a number of specific behavioral and psychiatric disorders and that the sib recurrence risk is around 4%. The purpose of this study is to determine whether children with Joubert and their families show behavioral or genetic characteristics similar to autism. Thirty-one volunteer Joubert families were identified. Parents completed a semi-structured family history interview and the Autism Behavioral Checklist. Rates of family loading for neuropsychiatric disorders in the JS families were compared to autism family history data and Down syndrome (DS) controls. The JS families had significantly lower rates of autism, alcoholism, cognitive, and language disorders than the autism families. Their rate of depression was lower, but not significantly different from that found in autism families. None of the JS children met the clinical cut-off for autism based on parental symptom report and the sib recurrence risk was 32% for the JS families compared to 4% for the autism and 0% for DS families. These data indicate that JS is a genetically distinct disorder from autism. Different genes with different inheritance patterns that affect neurodevelopment of the cerebellum could explain the clinical similarities previously reported in JS and autism.

Cytogenetic abnormalities and fragile-X syndrome in Autism Spectrum Disorder

BACKGROUND

Autism is a behavioral disorder with impaired social interaction, communication, and repetitive and stereotypic behaviors. About 5-10 % of individuals with autism have 'secondary' autism in which an environmental agent, chromosome abnormality, or single gene disorder can be identified. Ninety percent have idiopathic autism and a major gene has not yet been identified. We have assessed the incidence of chromosome abnormalities and Fragile X syndrome in a population of autistic patients referred to our laboratory.

METHODS

Data was analyzed from 433 patients with autistic traits tested using chromosome analysis and/or fluorescence in situ hybridization (FISH) and/or molecular testing for fragile X syndrome by Southern and PCR methods.

RESULTS

The median age was 4 years. Sex ratio was 4.5 males to 1 female [354:79]. A chromosome (cs) abnormality was found in 14/421 [3.33 %] cases. The aberrations were: 4/14 [28%] supernumerary markers; 4/14 [28%] deletions; 1/14 [7%] duplication; 3/14 [21%] inversions; 2/14 [14%] translocations. FISH was performed on 23 cases for reasons other than to characterize a previously identified cytogenetic abnormality. All 23 cases were negative. Fragile-X testing by Southern blots and PCR analysis found 7/316 [2.2 %] with an abnormal result. The mutations detected were: a full mutation (fM) and abnormal methylation in 3 [43 %], mosaic mutations with partial methylation of variable clinical significance in 3 [43%] and a permutation carrier [14%]. The frequency of chromosome and fragile-X abnormalities appears to be within the range in reported surveys (cs 4.8-1.7%, FRAX 2-4%). Limitations of our retrospective study include paucity of behavioral diagnostic information, and a specific clinical criterion for testing.

CONCLUSIONS

Twenty-eight percent of chromosome abnormalities detected in our study were subtle; therefore a high resolution cytogenetic study with a scrutiny of 15q11.2q13, 2q37 and Xp23.3 region should be standard practice when the indication is autism. The higher incidence of mosaic fragile-X mutations with partial methylation compared to FRAXA positive population [50% vs 15-40%] suggests that faint bands and variations in the Southern band pattern may occur in autistic patients.

The search for autism disease genes

Autism is a heritable disorder characterized by phenotypic and genetic complexity. This review begins by surveying current linkage, gene association, and cytogenetic studies performed with the goal of identifying autism disease susceptibility variants. Though numerous linkages and associations have been identified, they tend to diminish upon closer examination or attempted replication. The review therefore explores challenges to current methodologies presented by the complexities of autism that might underlie some of the current difficulties, and finishes by describing emerging phenotypic, statistical, and molecular investigational approaches that offer hope of overcoming those challenges.

Chromosomal anomalies in individuals with autism: a strategy towards the identification of genes involved in autism

We review the different strategies currently used to try to identify susceptibility genes for idiopathic autism. Although identification of genes is usually straightforward in Mendelian disorders, it has proved to be much more difficult to establish in polygenic disorders like autism. Neither genome screens of affected siblings nor the large number of association studies using candidate genes have resulted in finding autism susceptibility genes. We focus on the alternative approach of 'positional cloning' through chromosomal aberrations in individuals with autism. In particular, balanced aberrations such as reciprocal translocations or inversions offer a unique opportunity, since only the genes in the breakpoint regions are candidate genes. This approach, in combination with others, is likely to produce results in the coming years.

Children with autistic spectrum disorders. I: comparison of placebo and single dose of human synthetic secretin

AIMS

To examine the effect of a single dose of human synthetic secretin (HSS) on behaviour and communication in children with autism spectrum disorder (ASD) using an objective measure of communication and social reciprocity and standardised rating scales.

METHODS

Randomised, crossover, double blind, and placebo controlled trial of a single intravenous dose of human synthetic secretin (HSS) 2 CU/kg. The 62 subjects (3-8 years) were assigned to group 1 (saline placebo/HSS) or group 2 (HSS/saline placebo). Diagnosis was confirmed by ADI-R (Autism Diagnostic Interview-Revised) algorithm. Severity of symptoms was rated using the CARS (Childhood Autism Rating Scale). Outcome measures included Communication and Symbolic Behavior Scale (CSBS), Ritvo Real-life Rating Scale, weekly Global Rating Scale (GBRS) by parents and teachers, and daily log of gastrointestinal symptoms. The communication subscale of the CSBS, specifying communication function, reciprocity, and social-affective signalling was videotaped and scored by a blinded, trained observer.

RESULTS

Sixty one children completed the study. After randomisation, there were no significant differences in gender, race, age, and parent and teacher GBRS and Ritvo Scale between the two groups. Compared with placebo, secretin treatment was not associated with significant improvement of CSBS standard scores from baseline to 2 or 4 weeks post-infusion. Five children showed clinical improvement in standard scores: two after HSS and three after placebo. There were no significant changes in gastrointestinal symptoms after HSS or saline placebo.

CONCLUSIONS

A single dose of intravenous human secretin is not effective in changing behaviour and communication in children with ASD when compared to placebo.

Autism Diagnostic Interview-Revised and the Childhood Autism Rating Scale: convergence and discrepancy in diagnosing autism

The agreement between the Autism Diagnostic Interview-Revised (ADI-R) and the Childhood Autism Rating Scale (CARS) was investigated in the diagnostic assessment of 54 children aged 22-114 months referred for possible autism. The observed agreement between the two systems was 66.7% (Cohen's kappa = .40) when the ADI-R definition for autism was applied (i.e., scores reaching cutoff in three domains on the ADI-R), but increased considerably with less stringent criteria; that is, scores reaching cutoffs in two domains and in one domain on the ADI-R. As predicted, the CARS identified more cases of autism than the ADI-R. Children classified as autistic according to both instruments had significantly lower IQ/DQ and more severe autistic symptomatology than those classified with the CARS only.

The yield of the medical evaluation of children with pervasive developmental disorders

Little information is available regarding the yield of the medical evaluation of children diagnosed with pervasive developmental disorder-not otherwise specified (PDD-NOS) compared to children diagnosed with autistic disorder. Medical records were reviewed for 182 patients less than 18 years of age with either PDD-NOS or autistic disorder evaluated between 1994 and 1998 at Mayo Clinic. A condition likely to be etiologically relevant was identified in 6/117 (5.1%) patients diagnosed with PDD-NOS and 2/65 (3.1%) patients diagnosed with autistic disorder. Genetic disorders, both chromosomal and single-gene, were the most commonly identified conditions. Seizure disorders, electroencephalogram abnormalities, and anomalies on brain imaging were common in both groups. The likelihood of uncovering an etiologically relevant condition in children diagnosed with either PDD-NOS or autistic disorder may be equivalent. The scope of the etiological search in an individual patient with an autistic spectrum disorder should not be limited by the specific diagnostic category.

Identifying neurocognitive phenotypes in autism

Autism is a complex disorder that is heterogeneous both in its phenotypic expression and its etiology. The search for genes associated with autism and the neurobiological mechanisms that underlie its behavioural symptoms has been hampered by this heterogeneity. Recent studies indicate that within autism, there may be distinct subgroups that can be defined based on differences in neurocognitive profiles. This paper presents evidence for two kinds of subtypes in autism that are defined on the basis of language profiles and on the basis of cognitive profiles. The implications for genetic and neurobiological studies of these subgroups are discussed, with special reference to evidence relating these cognitive phenotypes to volumetric studies of brain size and organization in autism.

Co-occurrence of developmental disabilities with birth defects

This article begins with a discussion of the concepts of comorbidity and co-occurrence of diseases and health conditions. These concepts are then applied to the literature on the population-based prevalence of developmental disabilities and birth defects. Most of the existing literature focuses on co-occurrence and obtains data from both clinical and administrative sources. Developmental disabilities occur more frequently in children with multiple, rather than with isolated, birth defects. More research, with more sophisticated study designs, will be necessary to further elucidate the contributions of birth defects to the etiology of developmental disabilities, control for other risk factors, and to identify strategies for prevention and intervention services.

Medical disorders among inpatients with autism in Denmark according to ICD-8: a nationwide register-based study

Possible associations between autism and specific medical disorders have been suggested, and this could be of relevance in the clinical examination and treatment of patients and may help to identify factors involved in the etiology or pathophysiology of autism. Two population-based Danish registers were used to investigate the occurrence of medical disorders in patients with autism according to ICD-8 and in a matched control sample. A total of 29 of the 244 patients (11.9%) diagnosed with autism had one or more medical disorders. In contrast to previous studies, we did not find an increased occurrence of almost any medical disorders. A highly significant increased frequency of congenital malformations was found, which may indicate abnormalities in embryogenesis in the etiology of autism.

Asperger's disorder in the emergency psychiatric setting

Asperger's syndrome (AS) is a pervasive developmental disorder that may be unrecognized, especially if signs of other psychiatric disorders coexist. The objectives of this paper are: 1) to ascertain the prevalence of AS in the emergency psychiatric setting; and 2) to describe features of AS which may help to differentiate these patients from patients with psychotic disorders. Among 2500 patients admitted to a psychiatric intensive care unit, 5 (0.2%) received a diagnosis of AS, for the first time. Besides impairment of social interaction, common features were the following: male gender, left handedness, obsessive-compulsive symptoms, cognitive hyper-abilities, violent behavior, sense of humor, low WAIS total score, high WAIS verbal/performance score ratio, unusual, restricted interest and clumsiness. Comorbid schizophrenia is difficult to rule out in these patients. Psychotic symptoms should not be overvalued in making the diagnosis when specific features of AS are present.

Clinical considerations in the diagnosis of autism spectrum disorders

The diagnosis of autistic spectrum disorders (ASD) is being made more frequently in children and at younger ages. This paper discusses various factors to be considered in the screening of autism, early features of presentation, relevant to assessment and diagnosis, subtypes or different syndromes within the spectrum of autistic conditions including Asperger syndrome, the differential diagnosis from learning and language disorders and the medical and behavioural commonly associated disorders.

Fetal valproate syndrome and autism: additional evidence of an association

Autism has been described in association with a variety of medical and genetic conditions. We previously reported on a patient whose clinical phenotype was compatible with both fetal valproate syndrome (FVS) and autism. Here we present five additional patients with FVS and autism. In all five of our patients, there was evidence of cognitive deficits, manifestations of autism, and typical phenotypic characteristics of FVS. The association between this known teratogen and autism has both clinical and research implications.

The natural history of somatic morbidity in disintegrative psychosis and infantile autism: a validation study

In order to study the validity of disintegrative psychosis (DP) as defined in ICD-9, we compared the natural history of somatic morbidity of 13 patients given this diagnosis in childhood with a control group of 39 patients with infantile autism (IA) matched for gender, age, IQ and social class. Average follow-up time was 22 and 23 (11-33) years, respectively. Significantly more DP patients (85 versus 41%) had been admitted to a non-psychiatric hospital during the follow-up period. They also had significantly more admissions (3.6 versus 1.0) and stayed longer in hospital (78 versus 4 days) than patients with IA. Three of the DP individuals had an associated medical disorder and made extensive use of somatic services during the follow-up period. Altogether the DP group had utilised the medical health care system more than patients with IA suggesting that they had more medical symptoms than the IA group. On the whole our findings suggest that individuals with DP and IA should be conceptualised as essentially distinct and should be studied separately as regards aetiology, pathophysiology, course and treatment.