Regression in autism: prevalence and associated factors in the CHARGE Study

Patterns of skill attainment and loss in young children with autism

The purpose of this study was to extend the literature on the ontogeny of autism spectrum disorder (ASD) by examining early attainment and loss of specific sociocommunicative skills in children with autism (AUT; n = 125), pervasive developmental disorder not otherwise specified (PDD-NOS; n = 42), nonspectrum developmental delays (n = 46), and typical development (n = 31). The ages of skill attainment and loss were obtained from a caregiver interview. The findings indicated that children with AUT, PDD-NOS, and developmental delays diverged from typically developing children in attainment of sociocommunicative skills early in the first year of life. Loss of at least one skill was reported in a majority of children with AUT and PDD-NOS. Significant delays in attainment of skills were also reported in children who lost skills. The wide variation in skill attainment and loss reported across children indicates that symptom onset and regression may be best represented continuously, with at least some early delay and loss present for a great majority of children with ASD.

Heterogeneity within Autism Spectrum Disorders: What have We Learned from Neuroimaging Studies?

Autism spectrum disorders (ASD) display significant heterogeneity. Although most neuroimaging studies in ASD have been designed to identify commonalities among affected individuals, rather than differences, some studies have explored variation within ASD. There have been two general types of approaches used for this in the neuroimaging literature to date: comparison of subgroups within ASD, and analyses using dimensional measures to link clinical variation to brain differences. This review focuses on structural and functional magnetic resonance imaging studies that have used these approaches to begin to explore heterogeneity between individuals with ASD. Although this type of data is yet sparse, recognition is growing of the limitations of behaviorally defined categorical diagnoses for understanding neurobiology. Study designs that are more informative regarding the sources of heterogeneity in ASD have the potential to improve our understanding of the neurobiological processes underlying ASD.

Prevalence and onset of regression within autism spectrum disorders: a meta-analytic review

Rates and onset of regression were meta-analyzed from 85 articles representing 29,035 participants with autism spectrum disorders (ASD). Overall prevalence rate for regression was 32.1, 95 % CI [29.5, 34.8] occurring at mean of 1.78 years, 95 % CI [1.67, 1.89]. Regression prevalence rates differed according to four types of regression: language regression, 24.9 %; language/social regression, 38.1 %; mixed regression, 32.5 %; and unspecified regression, 39.1 %. Regression prevalence also differed according to sampling method: population-based prevalence was 21.8 %, clinic-based prevalence was 33.6 %, and parent survey-based prevalence was 40.8 %. Risk of regression was equal for males and females, but higher for individuals diagnosed with autism versus another ASD. Later age of regression onset was predicted by older age of child.

Thimerosal exposure and the role of sulfation chemistry and thiol availability in autism

Autism spectrum disorder (ASD) is a neurological disorder in which a significant number of the children experience a developmental regression characterized by a loss of previously acquired skills and abilities. Typically reported are losses of verbal, nonverbal, and social abilities. Several recent studies suggest that children diagnosed with an ASD have abnormal sulfation chemistry, limited thiol availability, and decreased glutathione (GSH) reserve capacity, resulting in a compromised oxidation/reduction (redox) and detoxification capacity. Research indicates that the availability of thiols, particularly GSH, can influence the effects of thimerosal (TM) and other mercury (Hg) compounds. TM is an organomercurial compound (49.55% Hg by weight) that has been, and continues to be, used as a preservative in many childhood vaccines, particularly in developing countries. Thiol-modulating mechanisms affecting the cytotoxicity of TM have been identified. Importantly, the emergence of ASD symptoms post-6 months of age temporally follows the administration of many childhood vaccines. The purpose of the present critical review is provide mechanistic insight regarding how limited thiol availability, abnormal sulfation chemistry, and decreased GSH reserve capacity in children with an ASD could make them more susceptible to the toxic effects of TM routinely administered as part of mandated childhood immunization schedules.

Evidence of neurodegeneration in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurological disorder in which a significant number of children experience a developmental regression characterized by a loss of previously-acquired skills and abilities. Loss of neurological function in ASD, as observed in affected children who have regressed, can be explained as neurodegeneration. Although there is research evidence of neurodegeneration or progressive encephalopathy in ASD, the issue of neurodegeneration in ASD is still under debate. Evidence of neurodegeneration in the brain in ASD includes: (1) neuronal cell loss, (2) activated microglia and astrocytes, (3) proinflammatory cytokines, (4) oxidative stress, and (5) elevated 8-oxo-guanosine levels. The evidence from this review suggests that neurodegeneration underlies the loss of neurological function in children with ASD who have experienced regression and loss of previously acquired skills and abilities, and that research into treatments to address the issue of neurodegeneration in ASD are warranted.

A review of embodiment in autism spectrum disorders

In classical approaches to cognition, sensory, motor, and emotional experiences are stripped of domain-specific perceptual and sensorimotor information, and represented in a relatively abstract form. In contrast, the embodied cognition framework suggests that our representations retain the initial imprint of the manner in which information was acquired. In this paper, we argue that individuals with autism spectrum disorders (ASD) display impairments in the temporal coordination of motor and conceptual information (as shown in gesture research) and striking deficits in the interpersonal mimicry of motor behaviors (as shown in yawning research) - findings we believe are consistent with an embodied account of ASD that includes, but goes beyond, social experiences and is driven in part by significant but subtle motor deficits. In this paper, we review the research examining an embodied cognition account of ASD, and discuss its implications.

Exploring the relationship between autism spectrum disorder and epilepsy using latent class cluster analysis

Epilepsy co-occurs frequently in autism spectrum disorders (ASD). Understanding this co-occurrence requires a better understanding of the ASD-epilepsy phenotype (or phenotypes). To address this, we conducted latent class cluster analysis (LCCA) on an ASD dataset (N = 577) which included 64 individuals with epilepsy. We identified a 5-cluster solution with one cluster showing a high rate of epilepsy (29%), earlier age at first recognition, and high rates of repetitive object use and unusual sensory interests. We also conducted LCCA on an ASD-epilepsy subset from the overall dataset (N = 64) which yielded three clusters, the largest of which had impairments in language and motor development; the remaining clusters, while not as developmentally impaired were characterized by different levels of repetitive and sensory behaviors.

Behavioral correlates of maternal antibody status among children with autism

Autism spectrum disorders (ASDs) affect approximately 1 in 110 children in the United States. This report profiles fetal-brain reactive autoantibodies of a large cohort of mothers of children with autism and controls, yielding significant associations between the presence of IgG reactivity to fetal brain proteins at 37 and 73 kDa and a childhood diagnosis of full autism (p = 0.0005), which also correlated with lower expressive language scores (p = 0.005). Additionally, we report on reactivity to proteins at 39 and 73 kDa, which correlated with the broader diagnosis of ASD (p = 0.0007) and increased irritability on the Aberrant Behavioral Checklist (p = 0.05). This study provides evidence of multiple patterns of reactivity to fetal brain proteins by maternal antibodies associated with ASD and specific childhood behavioral outcomes.

Modeling autism: a systems biology approach

Autism is the fastest growing developmental disorder in the world today. The prevalence of autism in the US has risen from 1 in 2500 in 1970 to 1 in 88 children today. People with autism present with repetitive movements and with social and communication impairments. These impairments can range from mild to profound. The estimated total lifetime societal cost of caring for one individual with autism is $3.2 million US dollars. With the rapid growth in this disorder and the great expense of caring for those with autism, it is imperative for both individuals and society that techniques be developed to model and understand autism. There is increasing evidence that those individuals diagnosed with autism present with highly diverse set of abnormalities affecting multiple systems of the body. To this date, little to no work has been done using a whole body systems biology approach to model the characteristics of this disorder. Identification and modelling of these systems might lead to new and improved treatment protocols, better diagnosis and treatment of the affected systems, which might lead to improved quality of life by themselves, and, in addition, might also help the core symptoms of autism due to the potential interconnections between the brain and nervous system with all these other systems being modeled. This paper first reviews research which shows that autism impacts many systems in the body, including the metabolic, mitochondrial, immunological, gastrointestinal and the neurological. These systems interact in complex and highly interdependent ways. Many of these disturbances have effects in most of the systems of the body. In particular, clinical evidence exists for increased oxidative stress, inflammation, and immune and mitochondrial dysfunction which can affect almost every cell in the body. Three promising research areas are discussed, hierarchical, subgroup analysis and modeling over time. This paper reviews some of the systems disturbed in autism and suggests several systems biology research areas. Autism poses a rich test bed for systems biology modeling techniques.

Classification of autism and related conditions: progress, challenges, and opportunities

Since Kanner's classic description of the syndrome of early infantile autism in 1943, conceptions of the disorder have evolved while retaining important continuity with what Kanner viewed as the hallmarks of the condition—social impairment (autism) and difficulties in dealing with change in the nonsocial world (insistence on sameness). This paper reviews the history of this evolution and the important potential advantages and disadvantages of changes being contemplated for DSM-5. The convergence of diagnostic approach in DSM-IV and ICD-10 provided a shared system that fostered a tremendous body of research. The changes proposed in DSM-5 may impact both research comparability and service eligibility.

Regression in children with autism spectrum disorders

OBJECTIVES

To understand the characteristics of autistic regression and to compare the clinical and developmental profile of children with autism spectrum disorders (ASD) in whom parents report developmental regression with age matched ASD children in whom no regression is reported.

METHODS

Participants were 35 (Mean age = 3.57 y, SD = 1.09) children with ASD in whom parents reported developmental regression before age 3 y and a group of age and IQ matched 35 ASD children in whom parents did not report regression. All children were recruited from the outpatient Child Psychology Clinic of the Department of Pediatrics of a tertiary care teaching hospital in North India. Multi-disciplinary evaluations including neurological, diagnostic, cognitive, and behavioral assessments were done. Parents were asked in detail about the age at onset of regression, type of regression, milestones lost, and event, if any, related to the regression. In addition, the Childhood Autism Rating Scale (CARS) was administered to assess symptom severity.

RESULTS

The mean age at regression was 22.43 mo (SD = 6.57) and large majority (66.7%) of the parents reported regression between 12 and 24 mo. Most (75%) of the parents of the regression-autistic group reported regression in the language domain, particularly in the expressive language sector, usually between 18 and 24 mo of age. Regression of language was not an isolated phenomenon and regression in other domains was also reported including social skills (75%), cognition (31.25%). In majority of the cases (75%) the regression reported was slow and subtle. There were no significant differences in the motor, social, self help, and communication functioning between the two groups as measured by the DP II.There were also no significant differences between the two groups on the total CARS score and total number of DSM IV symptoms endorsed. However, the regressed children had significantly (t = 2.36, P = .021) more social deficits as per the DSM IV as compared to the non-regressed children with autism.

CONCLUSIONS

Autism with regression is not characterized by a distinctive developmental or symptom profile. Developmental regression may, however, be an early and reliable marker in a significant number of children with autism.

Reduced activity of protein kinase C in the frontal cortex of subjects with regressive autism: relationship with developmental abnormalities

Autism is a neurodevelopmental disorder with unknown etiology. In some cases, typically developing children regress into clinical symptoms of autism, a condition known as regressive autism. Protein kinases are essential for G-protein-coupled receptor-mediated signal transduction, and are involved in neuronal functions, gene expression, memory, and cell differentiation. Recently, we reported decreased activity of protein kinase A (PKA) in the frontal cortex of subjects with regressive autism. In the present study, we analyzed the activity of protein kinase C (PKC) in the cerebellum and different regions of cerebral cortex from subjects with regressive autism, autistic subjects without clinical history of regression, and age-matched control subjects. In the frontal cortex of subjects with regressive autism, PKC activity was significantly decreased by 57.1% as compared to age-matched control subjects (p = 0.0085), and by 65.8% as compared to non-regressed autistic subjects (p = 0.0048). PKC activity was unaffected in the temporal, parietal and occipital cortices, and in the cerebellum in both autism groups, i.e., regressive and non-regressed autism as compared to control subjects. These results suggest brain region-specific alteration of PKC activity in the frontal cortex of subjects with regressive autism. Further studies showed a negative correlation between PKC activity and restrictive, repetitive and stereotyped pattern of behavior (r= -0.084, p = 0.0363) in autistic individuals, suggesting involvement of PKC in behavioral abnormalities in autism. These findings suggest that regression in autism may be attributed, in part, to alterations in G-protein-coupled receptor-mediated signal transduction involving PKA and PKC in the frontal cortex.

Risk factors for autistic regression: results of an ambispective cohort study

A subgroup of children diagnosed with autism experience developmental regression featured by a loss of previously acquired abilities. The pathogeny of autistic regression is unknown, although many risk factors likely exist. To better characterize autistic regression and investigate the association between autistic regression and potential influencing factors in Chinese autistic children, we conducted an ambispective study with a cohort of 170 autistic subjects. Analyses by multiple logistic regression showed significant correlations between autistic regression and febrile seizures (OR = 3.53, 95% CI = 1.17-10.65, P = .025), as well as with a family history of neuropsychiatric disorders (OR = 3.62, 95% CI = 1.35-9.71, P = .011). This study suggests that febrile seizures and family history of neuropsychiatric disorders are correlated with autistic regression.

Brief report: symptom onset patterns and functional outcomes in young children with autism spectrum disorders

This study examined the relationship between onset status and current functioning using a recently proposed onset classification system in 272 young children with autism spectrum disorder (ASD). Participants were classified into one of the following groups, based on parent report using the Autism Diagnostic Interview--Revised: Early Onset (symptoms by 12 months, no loss), Delay + Regression (symptoms by 12 months plus loss), Plateau (no early symptoms or loss), and Regression (no early symptoms, followed by loss). Findings indicate that current functioning does not differ according to onset pattern, calling into question the use of onset categorizations for prognostic purposes in children with ASD.

Patterns of developmental trajectories in toddlers with autism spectrum disorder

OBJECTIVE

Our objective was to follow toddlers referred for risk of autism, using standardized observational measures administered frequently from age 18 months to age 36 months.

METHOD

Sixty-five children who were consecutive referrals and 13 children from other research projects were seen approximately every 2 months, from age 18 months to age 36 months, for standardized assessments and clinical judgments by the same examiner and every 6 months by an examiner blind to previous scores.

RESULTS

Thirty children never received an autism spectrum disorder (ASD) diagnosis; 48 children (all referrals) received at least 1 diagnosis of ASD. The best trajectory typology, using Autism Diagnostic Observation Schedule (ADOS) scores, revealed 4 trajectory classes with high probabilities for fit to the most likely class: severe persistent (21%), worsening (21%), improving (19%), and nonspectrum (40%). Classes differed by trajectories in verbal and nonverbal mental ages; never-ever ASD groups differed on Autism Diagnostic Interview-Revised (ADI-R) domain scores and clinician judgments, but improving-worsening trajectory groups did not.

CONCLUSIONS

The results replicated the findings from studies of infants whose siblings have autism and infants whose siblings do not have autism, suggesting variability in early trajectories and supporting the need for early identification, regular monitoring, and standardized assessments of young children suspected of having ASD.

Autism spectrum disorders in Hispanics and non-Hispanics

OBJECTIVES

To compare differences in autism between Hispanic and non-Hispanics. We also examined the relationship between multiple language exposure and language function and scores of children.

METHODS

The Childhood Autism Risks from Genetics and the Environment (CHARGE) study is an ongoing population-based case-control study with children sampled (n=1061) from three strata: those with autism (AU) or autism spectrum disorder (ASD); developmental delay (DD); or the general population (GP).

RESULTS

Non-Hispanic cases demonstrated higher cognitive composite scores for the Mullen Scales of Early Learning (MSEL). There were significant associations between multiple language exposure and MSEL subscales for receptive language and expressive language, in both cases (AU/ASD) and TD controls, but not DD controls. Results of multivariate regression analyses suggest several predictors to be associated with lower Mullen expressive language scores including: diagnosis of ASD/AU, speaking to the child in a second language 25-50% of the time and Hispanic ethnicity; while maternal college education was associated with higher scores.

CONCLUSION

Overall, the CHARGE Hispanic group displayed more similarities than differences compared to non-Hispanics in terms of autistic phenotypes and maladaptive & adaptive scores for cases. The relationship between multiple language use and cognitive scores warrants a closer look.

Brain enlargement is associated with regression in preschool-age boys with autism spectrum disorders

Autism is a heterogeneous disorder with multiple behavioral and biological phenotypes. Accelerated brain growth during early childhood is a well-established biological feature of autism. Onset pattern, i.e., early onset or regressive, is an intensely studied behavioral phenotype of autism. There is currently little known, however, about whether, or how, onset status maps onto the abnormal brain growth. We examined the relationship between total brain volume and onset status in a large sample of 2- to 4-y-old boys and girls with autism spectrum disorder (ASD) [n = 53, no regression (nREG); n = 61, regression (REG)] and a comparison group of age-matched typically developing controls (n = 66). We also examined retrospective head circumference measurements from birth through 18 mo of age. We found that abnormal brain enlargement was most commonly found in boys with regressive autism. Brain size in boys without regression did not differ from controls. Retrospective head circumference measurements indicate that head circumference in boys with regressive autism is normal at birth but diverges from the other groups around 4-6 mo of age. There were no differences in brain size in girls with autism (n = 22, ASD; n = 24, controls). These results suggest that there may be distinct neural phenotypes associated with different onsets of autism. For boys with regressive autism, divergence in brain size occurs well before loss of skills is commonly reported. Thus, rapid head growth may be a risk factor for regressive autism.

Minor physical anomalies in children with autism spectrum disorders

OBJECTIVE

There is clinical heterogeneity among the autism spectrum disorders (ASD). The presence of dysmorphology (minor physical anomalies; MPAs) is one possible tool for defining a clinically relevant subset in ASD. This study employs an adaptation of Miles and Hillman's (2000) classifications by using photographs to identify a subgroup with significant dysmorphology among children with ASD, typical development (TYP), and developmental delay (DD).

METHOD

Children with ASD, DD, and TYP between 2 and 5 years old were part of the CHARGE Study. Pediatric specialists blinded to diagnostic group classified photographs based on the number of MPAs present: 'dysmorphic' if >3 and 'nondysmorphic' if <3 MPAs.

RESULTS

Photographs for 324 children were included. Significantly more children with ASD were classified as dysmorphic compared to TYP children (p = .007). In children with ASD, seizures were more prevalent in those rated dysmorphic (p = .005). Frequencies were similar between ASD versus DD (p = .19) after removing those with known syndromes.

CONCLUSION

Photographic assessment can be used to detect generalized dysmorphology in children who are often difficult to examine. This has clinical relevance, as children with multiple MPAs can be identified through the use of photographs and prioritized for investigation of brain abnormalities and underlying genetic disorders.

Does theory of mind performance differ in children with early-onset and regressive autism?

A deficit in theory of mind (ToM), or the ability to infer the mental states of others, has been implicated as one of the major characteristics of Autism Spectrum Disorder (ASD); however, little attention has been devoted to possible differences in ToM ability within ASD. The current study examined ToM performance in children with early-onset autism and regressive autism in comparison to typically developing children. Results indicated that children in the regressive autism group performed significantly better than the early-onset autism group on the non-verbal appearance-reality task. Additionally, Fisher's exact tests indicated a pattern of lowest scores in the early-onset group and highest scores in the typically developing group, whereas the regressive autism group tended to score in between the early-onset and typically developing groups. The apparent heterogeneity in ToM performance within ASD could account for the lack of universality in ToM ability found in previous studies.

Brain region-specific decrease in the activity and expression of protein kinase A in the frontal cortex of regressive autism

Autism is a severe neurodevelopmental disorder that is characterized by impaired language, communication, and social skills. In regressive autism, affected children first show signs of normal social and language development but eventually lose these skills and develop autistic behavior. Protein kinases are essential in G-protein-coupled, receptor-mediated signal transduction and are involved in neuronal functions, gene expression, memory, and cell differentiation. We studied the activity and expression of protein kinase A (PKA), a cyclic AMP–dependent protein kinase, in postmortem brain tissue samples from the frontal, temporal, parietal, and occipital cortices, and the cerebellum of individuals with regressive autism; autistic subjects without a clinical history of regression; and age-matched developmentally normal control subjects. The activity of PKA and the expression of PKA (C-α), a catalytic subunit of PKA, were significantly decreased in the frontal cortex of individuals with regressive autism compared to control subjects and individuals with non-regressive autism. Such changes were not observed in the cerebellum, or the cortices from the temporal, parietal, and occipital regions of the brain in subjects with regressive autism. In addition, there was no significant difference in PKA activity or expression of PKA (C-α) between non-regressive autism and control groups. These results suggest that regression in autism may be associated, in part, with decreased PKA-mediated phosphorylation of proteins and abnormalities in cellular signaling.

MAOA, DBH, and SLC6A4 variants in CHARGE: a case-control study of autism spectrum disorders

Genetic factors are established to contribute to the development of autism. We examined three loci, serotonin transporter (SLC6A4), dopamine β-hydroxylase (DBH), and the variable number of tandem repeat promoter of the monoamine oxidase A (MAOA) for association with autism in participants from the Childhood Autism Risks from Genetics and the Environment (CHARGE ) Study, the first large-scale population-based case-control investigation of both environmental and genetic contributions to autism risk. Among male children enrolled in the CHARGE study we tested associations between each of the three polymorphisms and autism (AU) (n = 119), or a combined group of autism and other autism spectrum disorders (AU+ASD, which includes an additional n = 53) as compared with typically developing controls (TD, n = 137). The case-control association analysis showed neither SLC6A4 nor DBH to be statistically significantly associated with AU or ASD. However, the male children carrying 4 tandem repeats in the promoter region of the MAOA gene showed a two-fold higher risk of AU (or AU+ASD) than those carrying allele 3, adjusted for confounders (OR = 2.02, 95% CI = 1.12, 3.65, P = 0.02 for AU vs. TD, and OR = 2.05, 95% CI = 1.19, 3.53, P = 0.01 for ASD vs. TD). In addition, children of mothers homozygous for the 4 tandem repeat allele showed at least a three-fold higher risk of AU (or AU+ASD) than those with mothers homozygous for allele 3 (OR = 3.07, 95% CI = 1.19, 7.91, P = 0.02 for AU vs. TD, and OR = 3.26, 95% CI = 1.35, 7.89, P = 0.009 for AU+ASD vs. TD). These results suggest a potential role of the functional MAOA promoter alleles in the male child, the mother, or both in ASD.

Onset patterns in autism: correspondence between home video and parent report

OBJECTIVE

The onset of autism is usually conceptualized as occurring in one of two patterns, early onset or regressive. This study examined the number and shape of trajectories of symptom onset evident in coded home movies of children with autism and examined their correspondence with parent report of onset.

METHOD

Four social-communicative behaviors were coded from the home video of children with autism (n = 52) or typical development (n = 23). All home videos from 6 through 24 months of age were coded (3199 segments). Latent class modeling was used to characterize trajectories and determine the optimal number needed to describe the coded home video. These trajectories were then compared with parent reports of onset patterns, as defined by the Autism Diagnostic Interview-Revised.

RESULTS

A three-trajectory model best fit the data from the participants with autism. One trajectory displayed low levels of social-communication across time. A second trajectory displayed high levels of social-communication early in life, followed by a significant decrease over time. A third trajectory displayed initial levels of behavior that were similar to the typically developing group but little progress in social-communication with age. There was poor correspondence between home video-based trajectories and parent report of onset.

CONCLUSIONS

More than two onset categories may be needed to describe the ways in which symptoms emerge in children with autism. There is low agreement between parent report and home video, suggesting that methods for improving parent report of early development must be developed.

The prevalence of gastrointestinal problems in children across the United States with autism spectrum disorders from families with multiple affected members

OBJECTIVE

: To perform a large registry-based study to determine the relative prevalence of gastrointestinal (GI) problems in children with an autism spectrum disorder (ASD) from families with multiple affected members compared with their unaffected sibling(s).

METHODS

: In-home structured retrospective medical history interviews by parent recall were conducted by a pediatric neurologist. Our analysis sample included information about GI health of 589 subjects with idiopathic, familial ASD and 163 of their unaffected sibling controls registered with Autism Genetic Resource Exchange. Individuals with ASD were subgrouped into 3 autism severity groups (Full Autism, Almost Autism, and Spectrum) based on their Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Scale scores.

RESULTS

: Parents reported significantly more GI problems in children with ASD (249/589; 42%) compared with their unaffected siblings (20/163; 12%) (p < .001). The 2 most common Gl problems in children with ASD were constipation (116/589; 20%) and chronic diarrhea (111/589; 19%). Conditional logistic regression analysis showed that having Full Autism (adjusted odds ratio [AOR] = 14.28, 95% confidence interval [CI]: 6.22-32.77) or Almost Autism (AOR = 5.16, 95% CI 2.02-13.21) was most highly associated with experiencing GI problems. Increased autism symptom severity was associated with higher odds of GI problems (AOR for trend = 2.63, 95% CI: 1.56-4.45).

CONCLUSIONS

: Parents report significantly more GI problems in children with familial ASD, especially those with Full Autism, than in their unaffected children. Increased autism symptom severity is associated with increased odds of having GI problems.

Brain region-specific deficit in mitochondrial electron transport chain complexes in children with autism

Mitochondria play important roles in generation of free radicals, ATP formation, and in apoptosis. We studied the levels of mitochondrial electron transport chain (ETC) complexes, that is, complexes I, II, III, IV, and V, in brain tissue samples from the cerebellum and the frontal, parietal, occipital, and temporal cortices of subjects with autism and age-matched control subjects. The subjects were divided into two groups according to their ages: Group A (children, ages 4-10 years) and Group B (adults, ages 14-39 years). In Group A, we observed significantly lower levels of complexes III and V in the cerebellum (p<0.05), of complex I in the frontal cortex (p<0.05), and of complexes II (p<0.01), III (p<0.01), and V (p<0.05) in the temporal cortex of children with autism as compared to age-matched control subjects, while none of the five ETC complexes was affected in the parietal and occipital cortices in subjects with autism. In the cerebellum and temporal cortex, no overlap was observed in the levels of these ETC complexes between subjects with autism and control subjects. In the frontal cortex of Group A, a lower level of ETC complexes was observed in a subset of autism cases, that is, 60% (3/5) for complexes I, II, and V, and 40% (2/5) for complexes III and IV. A striking observation was that the levels of ETC complexes were similar in adult subjects with autism and control subjects (Group B). A significant increase in the levels of lipid hydroperoxides, an oxidative stress marker, was also observed in the cerebellum and temporal cortex in the children with autism. These results suggest that the expression of ETC complexes is decreased in the cerebellum and the frontal and temporal regions of the brain in children with autism, which may lead to abnormal energy metabolism and oxidative stress. The deficits observed in the levels of ETC complexes in children with autism may readjust to normal levels by adulthood.

Polybrominated diphenyl ethers in relation to autism and developmental delay: a case-control study

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are flame retardants used widely and in increasing amounts in the U.S. over the last few decades. PBDEs and their metabolites cross the placenta and studies in rodents demonstrate neurodevelopmental toxicity from prenatal exposures. PBDE exposures occur both via breastfeeding and hand-to-mouth activities in small children.

METHODS

Participants were 100 children from the CHARGE (CHildhood Autism Risk from Genetics and the Environment) Study, a case-control epidemiologic investigation of children with autism/autism spectrum disorder, with developmental delay and from the general population. Diagnoses of autism were confirmed by the Autism Diagnostic Observation Schedule and Autism Diagnostic Inventory-Revised, and of developmental delay using the Mullen's Scales of Early Learning and the Vineland Adaptive Behavior Scales. Typically developing controls were those with no evidence of delay, autism, or autism spectrum disorder. Eleven PBDE congeners were measured by gas chromatography/mass spectrometry from serum specimens collected after children were assessed. Logistic regression was used to evaluate the association between plasma PBDEs and autism.

RESULTS

Children with autism/autism spectrum disorder and developmental delay were similar to typically developing controls for all PBDE congeners, but levels were high for all three groups.

CONCLUSIONS

Plasma samples collected post-diagnosis in this study may not represent early life exposures due to changes in diet and introduction of new household products containing PBDEs. Studies with direct measurements of prenatal or infant exposures are needed to assess the possible causal role for these compounds in autism spectrum disorders.

Elevated plasma cytokines in autism spectrum disorders provide evidence of immune dysfunction and are associated with impaired behavioral outcome

Autism spectrum disorders (ASD) are characterized by impairment in social interactions, communication deficits, and restricted repetitive interests and behaviors. A potential role for immune dysfunction has been suggested in ASD. To test this hypothesis, we investigated evidence of differential cytokine release in plasma samples obtained from 2 to 5 year-old children with ASD compared with age-matched typically developing (TD) children and children with developmental disabilities other than autism (DD). Participants were recruited as part of the population based case-control CHARGE (Childhood Autism Risks from Genetics and Environment) study and included: 97 participants with a confirmed diagnosis of ASD using standard assessments (DSM IV criteria and ADOS, ADI-R), 87 confirmed TD controls, and 39 confirmed DD controls. Plasma was isolated and cytokine production was assessed by multiplex Luminex™ analysis. Observations indicate significant increases in plasma levels of a number of cytokines, including IL-1β, IL-6, IL-8 and IL-12p40 in the ASD group compared with TD controls (p<0.04). Moreover, when the ASD group was separated based on the onset of symptoms, it was noted that the increased cytokine levels were predominantly in children who had a regressive form of ASD. In addition, increasing cytokine levels were associated with more impaired communication and aberrant behaviors. In conclusion, using larger number of participants than previous studies, we report significantly shifted cytokine profiles in ASD. These findings suggest that ongoing inflammatory responses may be linked to disturbances in behavior and require confirmation in larger replication studies. The characterization of immunological parameters in ASD has important implications for diagnosis, and should be considered when designing therapeutic strategies to treat core symptoms and behavioral impairments of ASD.

Medical treatment of autism spectrum disorders

PURPOSE OF REVIEW

There are several common medical conditions occurring in people with autism spectrum disorders (ASD) that can benefit from treatment and can in turn improve the health and quality of life of people with ASD. This review will primarily focus on these medical comorbidities, with a brief review of potential future treatments.

RECENT FINDINGS

There continues to be disagreement regarding the exact prevalence and etiological significance of gastrointestinal conditions, epilepsy and other abnormal electroencephalographic findings, and sleep problems. It is not clear whether gastrointestinal conditions occur more frequently than in typically developing children, and whether there are distinct conditions that occur more often in ASD than in non-ASD populations. Abnormal electroencephalographic findings have been reported in up to 60% of children with ASD, and some believe that these abnormalities may be responsible for parts of the ASD phenotype. Sleep problems are reported more frequently than in the general population, and effective treatments are available. Future medical treatments for ASD may be directed at underlying core symptoms and have greater impact than today's symptomatic approach.

SUMMARY

Further research in these areas is needed to better guide diagnosis and treatment of a variety of medical conditions experienced by people with ASD.

The prodrome of autism: early behavioral and biological signs, regression, peri- and post-natal development and genetics

Autism is one of the most heritable neurodevelopmental conditions and has an early onset, with symptoms being required to be present in the first 3 years of life in order to meet criteria for the 'core' disorder in the classification systems. As such, the focus on identifying a prodrome over the past 20 years has been on pre-clinical signs or indicators that will be present very early in life, certainly in infancy. A number of novel lines of investigation have been used to this end, including retrospective coding of home videos, prospective population screening and 'high risk' sibling studies; as well as the investigation of pre- and peri-natal, brain developmental and other biological factors. While no single prodromal sign is expected to be present in all cases, a picture is emerging of indicative prodromal signs in infancy and initial studies are being undertaken to attempt to ameliorate early presentation and even 'prevent' emergence of the full syndrome.

Healthcare for children with autism: the Autism Treatment Network

PURPOSE OF REVIEW

Autism spectrum disorders (ASDs) are a group of a neurodevelopmental disorders affecting social, communicative, and behavioral functioning. ASD is a heterogeneous group of disorders, often accompanied by associated medical issues. Thus, the development of effective treatments is a complex task requiring consideration of diverse etiologic and phenotypic characteristics. Recent attention to the diagnosis and treatment of medical conditions in ASD children has led to the formation of a new international collaboration to improve autism care, the Autism Treatment Network (ATN).

RECENT FINDINGS

Numerous studies have highlighted the high prevalence of gastrointestinal and sleep disorders among ASD children. Problems in communication - including being nonverbal - make the diagnosis and treatment of these conditions more difficult. Although a number of studies suggest links between neurologic impairments and gastrointestinal dysfunction and disordered sleep, these relationships remain unproven. Recent work by the ATN has begun the development of clinical guidelines in these areas, based on clinical consensus, adapting the model developed by the Cystic Fibrosis Foundation. New funding has also supported the network's development of a robust clinical research program focused on improving the physical health and care of children with ASD. These efforts promise more systematic and consistent approaches to diagnosis and treatment of these conditions.

SUMMARY

Improved understanding of the underlying pathology of ASD and associated conditions, and the development of a common purpose across multiple treating sites, can improve the consistent and coordinated healthcare of children with autism.

Reduced levels of immunoglobulin in children with autism correlates with behavioral symptoms

OBJECTIVES

To assay if plasma antibody levels in children with autism or developmental delays (DD) differ from those with typical development as an indicator of immune function and to correlate antibody levels with severity of behavioral symptoms.

METHODS

Plasma was collected from children with autistic disorder (AU; n=116), DD but not autism (n=32), autism spectrum disorder but not full autism (n=27), and age-matched typically developing (TD) controls (n=96). Samples were assayed for systemic levels of immunoglobulin (IgG, IgM, IgA, and IgE) by enzyme-linked immunosorbent assay. Subjects with autism were evaluated using the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview-Revised, and all subjects were scored on the Aberrant Behavior Checklist (ABC) by the parents. Numerical scores for each of the ABC subscales as well as the total scores were then correlated with Ig levels.

RESULTS

Children with AU have a significantly reduced level of plasma IgG (5.39+/-0.29 mg/mL) compared to the TD (7.72+/-0.28 mg/mL; P<0.001) and DD children (8.23+/-0.49 mg/mL; P<0.001). Children with autism also had a reduced level of plasma IgM (0.670.06 mg/mL) compared to TD (0.79+/-0.05 mg/mL; P<0.05). Ig levels were negatively correlated with ABC scores for all children (IgG: r=-0.334, P<0.0001; IgM: r=-0.167, P=0.0285).

CONCLUSION

Children with AU have significantly reduced levels of plasma IgG and IgM compared to both DD and TD controls, suggesting an underlying defect in immune function. This reduction in specific Ig levels correlates with behavioral severity, where those patients with the highest scores in the behavioral battery have the most reduced levels of IgG and IgM.

Loss of language in early development of autism and specific language impairment

BACKGROUND

Several authors have highlighted areas of overlap in symptoms and impairment among children with autism spectrum disorder (ASD) and children with specific language impairment (SLI). By contrast, loss of language and broadly defined regression have been reported as relatively specific to autism. We compare the incidence of language loss and language progression of children with autism and SLI.

METHODS

We used two complementary studies: the Special Needs and Autism Project (SNAP) and the Manchester Language Study (MLS) involving children with SLI. This yielded a combined sample of 368 children (305 males and 63 females) assessed in late childhood for autism, history of language loss, epilepsy, language abilities and nonverbal IQ.

RESULTS

language loss occurred in just 1% of children with SLI but in 15% of children classified as having autism or autism spectrum disorder. Loss was more common among children with autism rather than milder ASD and is much less frequently reported when language development is delayed. For children who lost language skills before their first phrases, the phrased speech milestone was postponed but long-term language skills were not significantly lower than children with autism but without loss. For the few who experienced language loss after acquiring phrased speech, subsequent cognitive performance is more uncertain.

CONCLUSIONS

Language loss is highly specific to ASD. The underlying developmental abnormality may be more prevalent than raw data might suggest, its possible presence being hidden for children whose language development is delayed.

The genetic and neurobiologic compass points toward common signaling dysfunctions in autism spectrum disorders

Autism spectrum disorder (ASD) is a common neurodevelopmental disorder with high heritability. Here, we discuss data supporting the view that there are at least two distinct genetic etiologies for ASD: rare, private (de novo) single gene mutations that may have a large effect in causing ASD; and inherited, common functional variants of a combination of genes, each having a small to moderate effect in increasing ASD risk. It also is possible that a combination of the two mechanisms may occur in some individuals with ASD. We further discuss evidence from individuals with a number of different neurodevelopmental syndromes, in which there is a high prevalence of ASD, that some private mutations and common variants converge on dysfunctional ERK and PI3K signaling, which negatively impacts neurodevelopmental events regulated by some receptor tyrosine kinases.

Regression of language and non-language skills in pervasive developmental disorders

BACKGROUND

As part of the pervasive developmental disorders (PDD), there is a subgroup of individuals reported to have a different onset of symptom appearance consisting of an apparently normal early development, followed by a loss of verbal and/or non-verbal skills prior to 2 years of age. This study aims at comparing the symptomatology of children who displayed a regression and often an associated intellectual disability through investigation of two types of loss, namely language and other skill regression.

METHODS

This study examined the occurrence of regression in 135 children with PDD, mean age 6.3 years. The sample was composed of 80 (59.4%) children diagnosed with autism, 44 (32.6%) with pervasive developmental disorder-not otherwise specified (PDD-NOS) and 11 (8%) with Asperger syndrome. The Autism Diagnostic Interview Revised (ADI-R) was used to evaluate the type of loss and to characterise associated factors including birth rank, gender and thimerosal exposure through vaccination.

RESULTS

A total of 30 (22%) subjects regressed: nine (30%) underwent language regression alone, 17 (57%) lost a skill other than language and four (13%) lost both language and another skill. Significantly higher levels of regression were found in autism (30%) compared with PDD-NOS (14%) and Asperger syndrome (0%). Children who regressed in language skills spoke at a significantly earlier age ( = 12 months) than those who did not regress in this domain ( = 26 months). Parents and interviewers consistently reported developmental abnormalities prior to the loss. ADI-R domain mean scores indicated a more severe autistic symptomatology profile in children who regressed compared with those who did not, especially in the repetitive behaviour domain. Regression was not associated to thimerosal exposure, indirectly estimated by year of birth.

CONCLUSIONS

A loss of skill, present in one out of five children with PDD, is associated with a slightly more severe symptomatology as measured by the ADI-R, particularly in the repetitive behaviours domain. Furthermore, although abnormalities are often noticed by the caregivers at the time of regression, the ADI-R reveals that other atypical behaviours were in fact present prior to the onset of regression in most cases. None of the secondary factors investigated were associated with regression. In children unexposed to thimerosal-containing vaccines, the rate of regression was similar to that reported in studies of samples exposed to thimerosal, suggesting that thimerosal has no specific association with regressive autism.

Detection of autoantibodies to neural cells of the cerebellum in the plasma of subjects with autism spectrum disorders

Autism spectrum disorders (ASD) are a group of heterogeneous, behaviorally defined disorders characterized by disturbances in social interaction and communication, often with repetitive and stereotyped behavior. Previous studies have described the presence of antibodies to various neural proteins in autistic individuals as well as post-mortem evidence of neuropathology in the cerebellum. We examined plasma from children with ASD, as well as age-matched typically developing controls, for antibodies directed against human cerebellar protein extracts using Western blot analysis. In addition, the presence of cerebellar specific antibodies was assessed by immunohistochemical staining of sections from Macaca fascicularis monkey cerebellum. Western blot analysis revealed that 13/63 (21%) of subjects with ASD possessed antibodies that demonstrated specific reactivity to a cerebellar protein with an apparent molecular weight of approximately 52 kDa compared with only 1/63 (2%) of the typically developing controls (p=0.0010). Intense immunoreactivity, to what was determined morphologically to be the Golgi cell of the cerebellum, was noted for 7/34 (21%) of subjects with ASD, compared with 0/23 of the typically developing controls. Furthermore, there was a strong association between the presence of antibodies reactive to the 52 kDa protein by Western blot with positive immunohistochemical staining of cerebellar Golgi cells in the ASD group (r=0.76; p=0.001) but not controls. These studies suggest that when compared with age-matched typically developing controls, children with ASD exhibit a differential antibody response to specific cells located in the cerebellum and this response may be associated with a protein of approximately 52 kDa.

Advances in autism

Autism is a common childhood neurodevelopmental disorder with strong genetic liability. It is not a unitary entity but a clinical syndrome, with variable deficits in social behavior and language, restrictive interests, and repetitive behaviors. Recent advances in the genetics of autism emphasize its etiological heterogeneity, with each genetic susceptibility locus accounting for only a small fraction of cases or having a small effect. Therefore, it is not surprising that no unifying structural or neuropathological features have been conclusively identified. Given the heterogeneity of autism spectrum disorder (ASD), approaches based on studying heritable components of the disorder, or endophenotypes, such as language or social cognition, provide promising avenues for genetic and neurobiological investigations. Early intensive behavioral and cognitive interventions are efficacious in many cases, but autism does not remit in the majority of children. Therefore, development of targeted therapies based on pathophysiologically and etiologically defined subtypes of ASD remains an important and achievable goal of current research.

The onset of autism: patterns of symptom emergence in the first years of life

Previous conceptualizations of autism have suggested that symptoms are evident either early in the first year of life or later in the second year, after a loss of previously acquired skills. New research suggests, however, that these two patterns do not capture all the different ways autism can emerge. For example, some children show a developmental plateau marked by failure to progress, while other children display mixed features, with both early delays and later losses evident. This article reviews the literature on autism onset, discusses problems with the traditional ways in which onset has been conceptualized, and provides recommendations for future research. We suggest that onset is better thought of as a dimensional process rather than dichotomous categories.

Regression in autistic spectrum disorders

A significant proportion of children diagnosed with Autistic Spectrum Disorder experience a developmental regression characterized by a loss of previously-acquired skills. This may involve a loss of speech or social responsitivity, but often entails both. This paper critically reviews the phenomena of regression in autistic spectrum disorders, highlighting the characteristics of regression, age of onset, temporal course, and long-term outcome. Important considerations for diagnosis are discussed and multiple etiological factors currently hypothesized to underlie the phenomenon are reviewed. It is argued that regressive autistic spectrum disorders can be conceptualized on a spectrum with other regressive disorders that may share common pathophysiological features. The implications of this viewpoint are discussed.