A pilot study to evaluate nutritional influences on gastrointestinal symptoms and behavior patterns in children with Autism Spectrum Disorder

Role of gastrointestinal health in managing children with autism spectrum disorder

Children with autism spectrum disorders (ASD) or autism are more prone to gastrointestinal (GI) disorders than the general population. These disorders can significantly affect their health, learning, and development due to various factors such as genetics, environment, and behavior. The causes of GI disorders in children with ASD can include gut dysbiosis, immune dysfunction, food sensitivities, digestive enzyme deficiencies, and sensory processing differences. Many studies suggest that numerous children with ASD experience GI problems, and effective management is crucial. Diagnosing autism is typically done through genetic, neurological, functional, and behavioral assessments and observations, while GI tests are not consistently reliable. Some GI tests may increase the risk of developing ASD or exacerbating symptoms. Addressing GI issues in individuals with ASD can improve their overall well-being, leading to better behavior, cognitive function, and educational abilities. Proper management can improve digestion, nutrient absorption, and appetite by relieving physical discomfort and pain. Alleviating GI symptoms can improve sleep patterns, increase energy levels, and contribute to a general sense of well-being, ultimately leading to a better quality of life for the individual and improved family dynamics. The primary goal of GI interventions is to improve nutritional status, reduce symptom severity, promote a balanced mood, and increase patient independence.

Low Levels of Detectable Urine and Stool GIPs in Children with Celiac Disease on a Gluten-Free Diet

Objectives

This study examines the prevalence of detectable gluten immunogenic peptides (GIPs) as a proxy for gluten exposure in children with celiac disease on a gluten-free diet in the United States, as estimated by gluten breakdown products excreted in urine and stool.

Methods

Urine and stool samples were collected in 3 settings (home, gastroenterology clinic, and endoscopy) for pediatric participants (ages 6-21 years old) across 2 medical centers. Commercial ELISA assays were used to quantify the GIPs in each sample.

Results

GIPs were detected in 4 out of 44 (9.1%) of stool samples and 6 out of 125 (4.8%) of urine samples provided by 84 children. These samples were collected across all settings, and most participants (70%) were asymptomatic at the time of sample collection. For the urine samples collected at the time of endoscopy, all subjects found to have persistent enteropathy had no detectable GIPs (0/12).

Discussion

GIPs provide an additional method for screening for gluten exposures in individuals with celiac disease on a gluten-free diet, and may be used across multiple settings. We found a low detection rate of GIPs in children. Our finding of undetectable GIPs in individuals with persistent enteropathy may be expected of a single determination under close observation or represent a lack of gluten exposure within the detection window. More research is needed to understand the dynamics of gluten absorption and excretion in the US pediatric population.

Celiac disease screening at a pediatric outpatient clinic: a feasibility study

OBJECTIVES

Celiac disease (CD) is a common yet largely underdiagnosed disease. This study aimed to test the feasibility of incorporating a non-targeted CD screening in a pediatric outpatient setting and evaluate its short-term impact on children with serological evidence of disease.

METHODS

Over five months, 500 children (aged 2-17 years) attending a general pediatric outpatient clinic in Gothenburg, Sweden, were enrolled and surveyed for current symptoms, quality of life, and background characteristics; 481 children were screened for tissue-transglutaminase antibodies (tTGA); repeated tTGA-positivity was defined as CD autoimmunity (CDA). Children with CDA were investigated for CD and for one year monitored for changes in symptoms, and quality of life.

RESULTS

Eleven of 481 (2.3%) screened children had CDA. Children with CDA were younger (median 3.8 years) than those without CDA (8.8 years). No other major between-group differences were reported in background characteristics, symptoms, or quality of life. The screening was well-accepted by the families/participants. During 1-year follow-up, 8 of 11 children with CDA were diagnosed with CD. Children with screening-detected CD reported no significant changes in symptoms and quality of life and the dietary adherence rate was good.

CONCLUSIONS

Non-targeted screening for CD was feasible in a general pediatric outpatient setting. While hampered by small sample size, our results are in line with previous screening studies indicating that symptoms do not differentiate CDA from non-CDA children. Also, among an overall minimal-symptomatic group of children, diagnosing CD and installation of treatment did not significantly change their well-being during 1-year follow-up.

A Scoping Literature Review of the Relation between Nutrition and ASD Symptoms in Children

Autism spectrum disorder (ASD) is characterized by impairments in social interaction, communication skills, and repetitive and restrictive behaviors and interests. Even though there is a biological basis for an effect of specific nutrition factors on ASD symptoms and there is scientific literature available on this relationship, whether nutrition factors could play a role in ASD treatment is unclear. The goal of the current literature review was to summarize the available scientific literature on the relation between nutrition and autism spectrum disorder (ASD) symptoms in childhood, and to formulate practical dietary guidelines. A comprehensive search strategy including terms for ASD, nutrition factors (therapeutic diets, dietary patterns, specific food products, fatty acids and micronutrients) and childhood was developed and executed in six literature databases (Cinahl, Cochrane, Ovid Embase, PsycInfo, PubMed and Web of Science). Data from meta-analyses, systematic reviews and original studies were qualitatively summarized. A total of 5 meta-analyses, 29 systematic reviews and 27 original studies were retrieved that focused on therapeutic diets, specific food products, fatty acids and micronutrients and ASD symptoms during childhood. Results of the available studies were sparse and inconclusive, and hence, no firm conclusions could be drawn. There is currently insufficient evidence for a relation between nutrition and ASD symptoms in childhood, making it impossible to provide practical nutrition guidelines; more methodological sound research is needed.

Repetitive Restricted Behaviors in Autism Spectrum Disorder: From Mechanism to Development of Therapeutics

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by deficits in social communication, social interaction, and repetitive restricted behaviors (RRBs). It is usually detected in early childhood. RRBs are behavioral patterns characterized by repetition, inflexibility, invariance, inappropriateness, and frequent lack of obvious function or specific purpose. To date, the classification of RRBs is contentious. Understanding the potential mechanisms of RRBs in children with ASD, such as neural connectivity disorders and abnormal immune functions, will contribute to finding new therapeutic targets. Although behavioral intervention remains the most effective and safe strategy for RRBs treatment, some promising drugs and new treatment options (e.g., supplementary and cell therapy) have shown positive effects on RRBs in recent studies. In this review, we summarize the latest advances of RRBs from mechanistic to therapeutic approaches and propose potential future directions in research on RRBs.

The opioid excess theory in autism spectrum disorders - is it worth investigating further?

Autism spectrum disorders (ASD) are defined as neurodevelopmental disorders, which are highly variable in nature and do not form a uniform picture, either in terms of symptomatology or depth of the disturbance. Diagnosis of ASD is made for children who show signs of impairment in social interaction, communication and cognitive skills. The exact cause of autism spectrum disorders has not been determined to date. Although there is no cure for ASD, a variety interventions have been proposed. The most commonly used restrictive dietary intervention is the gluten-free casein-free diet (GFCF), which is based on the opioid excess theory. This paper summarizes and discusses research on the core elements of the opioid excess theory in ASD: increased levels of opioid peptides in body fluids in ASD patients, increased intestinal permeability, altered peptidase activity and the effectiveness of GFCF diet in alleviating symptoms of ASD. Furthermore, we discuss the difficulties and their causes in conducting research with ASD patients. The assumptions of the opioid excess theory have neither been definitively confirmed nor disproved. Research in this area should continue, taking into account the highest possible quality standards and the specific needs and abilities of patients with ASD and their families.

A systematic review and meta-analysis of the benefits of a gluten-free diet and/or casein-free diet for children with autism spectrum disorder

CONTEXT

It has been suggested that a gluten-free and casein-free (GFCF) diet may alleviate the symptoms of autism spectrum disorder (ASD) and facilitate neurodevelopment of children with ASD. Studies to date have been inconclusive.

OBJECTIVE

This study aimed to evaluate (through quantitative meta-analysis) the efficacy and safety of a GFCF diet for children with ASD. To our knowledge, this is the first time such an analysis has been carried out.

DATA SOURCES

Eight electronic databases were searched, from the establishment of each database up to March 27, 2020: PubMed, Web of Science, Embase (Ovid), PsycINFO (Ovid), Cochrane Library, CNKI, Wanfang, and VIP databases.

DATA EXTRACTION

Two authors independently performed the data extraction and risk-of-bias assessment.

DATA ANALYSIS

A quantitative meta-analysis was performed with standard procedures by using Stata SE 15 software. Within the total of 8 studies, with 297 participants, 5 studies reported significant reductions in stereotypical behaviors [standard mean difference (SMD) = -0.41, 95% confidence interval (CI): -0.68 to -0.15], and 3 studies reported improvements in cognition (SMD = -0.46, 95% CI: -0.91 to -0.01) following GFCF dietary intervention. No statistically significant changes were observed in other symptomatic categories (all P > 0.05).

CONCLUSION

The current meta-analysis showed that a GFCF diet can reduce stereotypical behaviors and improve the cognition of children with ASD. Though most of the included studies were single-blind, the benefits of a GFCF diet that have been indicated are promising. Additional studies on a larger scale are warranted.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020177619.

Gluten and Autism Spectrum Disorder

An expanding body of literature is examining connections between Autism Spectrum Disorder (ASD) and dietary interventions. While a number of specialist diets have been suggested as beneficial in ASD, gluten has received particularly close attention as a potentially exacerbating factor. Reports exist suggesting a beneficial effect of the gluten-free diet (GFD) in ameliorating behavioural and intellectual problems associated with ASD, while epidemiological research has also shown a comorbidity between ASD and coeliac disease. However, both caregivers and clinicians have expressed an uncertainty of the value of people with ASD going gluten-free, and as the GFD otherwise receives considerable public attention a discussion which focuses specifically on the interaction between ASD and gluten is warranted. In this review we discuss the historical context of ASD and gluten-related studies, and expand this to include an overview of epidemiological links, hypotheses of shared pathological mechanisms, and ultimately the evidence around the use and adoption of the GFD in people with ASD.

Dietary Approaches to the Management of Autism Spectrum Disorders

This chapter reviews the literature surrounding autism spectrum disorders (ASD) and their relation to gastrointestinal (GI), behavioral, neurological, and immunological functioning. Individuals with ASD often have poor GI health, including bowel motility issues, autoimmune and/or other adverse responses to certain foods, and lack of necessary nutrient absorption. These issues may be caused or exacerbated by restrictive behavioral patterns (e.g., preference for sweet and salty foods and/or refusal of healthy foods). Those individuals with GI issues tend to demonstrate more behavioral deficits (e.g., irritability, agitation, hyperactivity) and also tend to have an imbalance in overall gut microbiome composition, thus corroborating several studies that have implicated brain-gut pathways as potential mediators of behavioral dysfunction.We examine the literature regarding dietary approaches to managing ASDs, including elimination diets for gluten, casein, or complex carbohydrates, a ketogenic diet, and a low oxalate diet. We also explore the research examining dietary supplements such as fatty acids, pro- and prebiotics, vitamins, minerals, glutathione, phytochemicals, and hormones. The research on dietary approaches to managing ASDs is limited and the results are mixed. However, a few approaches, such as the gluten-free/casein-free diet, fatty acid supplementation, and pre/probiotics have generally demonstrated improved GI and associated behavioral symptoms. Given that GI issues seem to be overrepresented in ASD populations, and that GI issues have been associated with a number behavioral and neurological deficits, dietary manipulation may offer a cheap and easily implemented approach to improve the lives of those with ASD.

Pharmacological, non-pharmacological and stem cell therapies for the management of autism spectrum disorders: A focus on human studies

In the last decade, the prevalence of autism spectrum disorders (ASD) has dramatically escalated worldwide. Currently available drugs mainly target some co-occurring symptoms of ASD, but are not effective on the core symptoms, namely impairments in communication and social interaction, and the presence of restricted and repetitive behaviors. On the other hand, transplantation of hematopoietic and mesenchymal stem cells in ASD children has been shown promising to stimulate the recruitment, proliferation, and differentiation of tissue-residing native stem cells, reducing inflammation, and improving some ASD symptoms. Moreover, several comorbidities have also been associated with ASD, such as immune dysregulation, gastrointestinal issues and gut microbiota dysbiosis. Non-pharmacological approaches, such as dietary supplementations with certain vitamins, omega-3 polyunsaturated fatty acids, probiotics, some phytochemicals (e.g., luteolin and sulforaphane), or overall diet interventions (e.g., gluten free and casein free diets) have been considered for the reduction of such comorbidities and the management of ASD. Here, interventional studies describing pharmacological and non-pharmacological treatments in ASD children and adolescents, along with stem cell-based therapies, are reviewed.

HLA-DQ Genotyping, Duodenal Histology, and Response to Exclusion Diet in Autistic Children With Gastrointestinal Symptoms

OBJECTIVES

A correlation between autism spectrum disorders (ASDs) and gastrointestinal (GI) problems, and a possible link between gluten consumption and ASD have been increasingly reported. Gluten/casein-free diet (GCFD) is often undertaken, with conflicting results. This study aimed at evaluating the distribution of human leukocyte antigen (HLA)-DQ2/DQ8 typing among patients with ASD with GI symptoms, together with its correlation with duodenal histology and response to GCFD.

METHODS

Between 2002 and 2015 all patients with ASD with GI symptoms referred to our outpatient clinic, displaying clinical, laboratory, or ultrasound findings suggestive of organic disease, underwent endoscopy, celiac disease (CD) serum antibodies testing and HLA-DQ2/DQ8 genotyping. Patients were prescribed a 6-month GCFD, and then clinically reassessed.

RESULTS

Among 151 enrolled patients, 134 (89%) were negative for CD-specific antibodies; 72 (48%) were positive for HLA-DQ2/DQ8; and 56 (37%) showed duodenal microscopic inflammation. Clinical improvement was observed in non-CD patients irrespective of the rigorous or partial adherence to the diet, being the difference nonstatistically significant. Response to diet was related to the presence of histological duodenal alterations at baseline (odds ratio 11.323, 95% confidence interval 1.386-92.549 for Marsh 2 pattern), but not to HLA-DQ2/DQ8 positivity (odds ratio 1.120, 95% confidence interval 0.462-2.716).

CONCLUSIONS

Our data suggest that children with ASD with GI symptoms have a high prevalence of duodenal intraepithelial lymphocytic infiltration, which seems to be linked to a mechanism other than autoimmune response to gluten consumption. Alteration of duodenal histology, but not the HLA-DQ2/DQ8 status, was associated with clinical response to the diet.

Dietary approach and gut microbiota modulation for chronic hepatic encephalopathy in cirrhosis

Hepatic encephalopathy (HE) is a common and serious neuropsychiatric complication of cirrhosis, acute liver failure, and porto-systemic shunting. HE largely contributes to the morbidity of patients with liver disease, severely affecting the quality of life of both patients and their relatives and being associated with poor prognosis. Its presentation is largely variable, manifesting with a broad spectrum of cognitive abnormalities ranging from subtle cognitive impairment to coma. The pathogenesis of HE is complex and has historically been linked with hyperammonemia. However, in the last years, it has become evident that the interplay of multiple actors, such as intestinal dysbiosis, gut hyperpermeability, and neuroinflammation, is of crucial importance in its genesis. Therefore, HE can be considered a result of a dysregulated gut-liver-brain axis function, where cognitive impairment can be reversed or prevented by the beneficial effects induced by "gut-centric" therapies, such as non-absorbable disaccharides, non-absorbable antibiotics, probiotics, prebiotics, and fecal microbiota transplantation. In this context dietary modifications, by modulating the intestinal milieu, can also provide significant benefit to cirrhotic patients with HE. This review will provide a comprehensive insight into the mechanisms responsible for gut-liver-brain axis dysregulation leading to HE in cirrhosis. Furthermore, it will explore the currently available therapies and the most promising future treatments for the management of patients with HE, with a special focus on the dietary approach.

Lack of Associations Between Dietary Intake and Gastrointestinal Symptoms in Autism Spectrum Disorder

Background: Many individuals with autism spectrum disorder (ASD) have significant gastrointestinal (GI) symptoms, but their etiology is currently unknown. Dietary interventions are common in children and adolescents with ASD, including diets with increased omega-3 fatty acids or diets free of gluten and/or casein, which may also impact GI symptoms and nutrition. However, little is known about the relationship between nutritional intake and GI symptomatology in ASD. The objective of this study was to assess the relationships between GI symptoms, omega-3 intake, micronutrients, and macronutrients in children with ASD. Methods: A total of 120 children diagnosed with ASD participated in this multisite study. A food frequency questionnaire was completed by the patient's caretaker. The USDA Food Composition Database was utilized to provide nutritional data for the food items consumed by each participant. GI symptomatology was assessed using a validated questionnaire on pediatric gastrointestinal symptoms. Results: There were no significant associations between GI symptoms and the amount of omega-3 fatty acids and/or other micro- and macronutrients contained in the diet. Conclusions: This study suggests that dietary variations do not appear to drive GI symptoms, nor do GI symptoms drive dietary variations in those with ASD, although causation cannot be determined with this observational assessment. Furthermore, there may be other factors associated with lower GI tract symptoms in ASD, such as increased stress response.

Oral Health for US Children with Special Health Care Needs

Children with special health care needs (CSHCN) are a vulnerable population subgroup, but little is known about their oral health, particularly regarding the prevalence and cause of tooth decay. This lack of knowledge is a barrier to progress in terms of developing evidence-based clinical interventions and policies aimed at promoting oral health in CSHCN. This article reviews the oral health literature pertaining to CSHCN, identifies critical knowledge gaps, highlights future research opportunities, and extends clinical recommendations to pediatric health care providers.

A prebiotic intervention study in children with autism spectrum disorders (ASDs)

BACKGROUND

Different dietary approaches, such as gluten and casein free diets, or the use of probiotics and prebiotics have been suggested in autistic spectrum disorders in order to reduce gastrointestinal (GI) disturbances. GI symptoms are of particular interest in this population due to prevalence and correlation with the severity of behavioural traits. Nowadays, there is lack of strong evidence about the effect of dietary interventions on these problems, particularly prebiotics. Therefore, we assessed the impact of exclusion diets and a 6-week Bimuno® galactooligosaccharide (B-GOS®) prebiotic intervention in 30 autistic children.

RESULTS

The results showed that children on exclusion diets reported significantly lower scores of abdominal pain and bowel movement, as well as lower abundance of Bifidobacterium spp. and Veillonellaceae family, but higher presence of Faecalibacterium prausnitzii and Bacteroides spp. In addition, significant correlations were found between bacterial populations and faecal amino acids in this group, compared to children following an unrestricted diet. Following B-GOS® intervention, we observed improvements in anti-social behaviour, significant increase of Lachnospiraceae family, and significant changes in faecal and urine metabolites.

CONCLUSIONS

To our knowledge, this is the first study where the effect of exclusion diets and prebiotics has been evaluated in autism, showing potential beneficial effects. A combined dietary approach resulted in significant changes in gut microbiota composition and metabolism suggesting that multiple interventions might be more relevant for the improvement of these aspects as well as psychological traits.

TRIAL REGISTRATION

NCT02720900 ; registered in November 2015.

Are therapeutic diets an emerging additional choice in autism spectrum disorder management?

BACKGROUND

A nutritional background has been recognized in the pathophysiology of autism and a series of nutritional interventions have been considered as complementary therapeutic options. As available treatments and interventions are not effective in all individuals, new therapies could broaden management options for these patients. Our aim is to provide current literature data about the effect of therapeutic diets on autism spectrum disorder.

DATA SOURCE

A systematic review was conducted by two reviewers independently. Prospective clinical and preclinical studies were considered.

RESULT

Therapeutic diets that have been used in children with autism include ketogenic and gluten/casein-free diet. We were able to identify 8 studies conducted in animal models of autism demonstrating a beneficial effect on neurophysiological and clinical parameters. Only 1 clinical study was found showing improvement in childhood autism rating scale after implementation of ketogenic diet. With regard to gluten/casein-free diet, 4 clinical studies were totally found with 2 of them showing a favorable outcome in children with autism. Furthermore, a combination of gluten-free and modified ketogenic diet in a study had a positive effect on social affect scores. No serious adverse events have been reported.

CONCLUSION

Despite encouraging laboratory data, there is controversy about the real clinical effect of therapeutic diets in patients with autism. More research is needed to provide sounder scientific evidence.

Effect of gluten free diet on gastrointestinal and behavioral indices for children with autism spectrum disorders: a randomized clinical trial

BACKGROUND

Genetic and environmental factors are both responsible for the etiology of autism spectrum disorders (ASD). Although epidemiological studies have been conducted to clarify the association between restriction diets and ASD, the conclusion remains unclear. This study was undertaken to investigate the effect of gluten free diet (GFD) on gastrointestinal symptoms and behavioral indices in children with ASD.

METHODS

In this randomized clinical trial, 80 children diagnosed with ASD by the Autism Diagnostic Interview-Revised (ADI-R) were assigned into GFD (n=40) and regular diet (RD) (n=40) groups for 6 weeks. At the beginning and end of the intervention, the ROME Ш questionnaire for evaluating gastrointestinal symptoms and Gilliam Autism Rating Scale 2 questionnaire (GARS-2) for assessing psychometric properties were completed.

RESULTS

Of the 80 children, 53.9% had gastrointestinal abnormalities. In the GFD group, the prevalence of gastrointestinal symptoms decreased significantly (P<0.05) after intake of GFD (40.57% vs. 17.10%) but increased insignificantly in the RD group (42.45% vs. 44.05%). GFD intervention resulted in a significant decrease in behavioral disorders (80.03±14.07 vs. 75.82±15.37, P<0.05) but an insignificant increase in the RD group (79.92±15.49 vs. 80.92±16.24).

CONCLUSION

This study suggested that GFD may be effective in controlling gastrointestinal symptoms and ASD behaviors.

A review of gluten- and casein-free diets for treatment of autism: 2005-2015

BACKGROUND

The gluten free, casein free (GFCF) diet is heralded by strong anecdotal parental reports to greatly improve and even "cure" symptoms of Autism Spectrum Disorders (ASD). Yet to date, little conclusive empirical evidence exists supporting its use.

OBJECTIVE

The purpose of this paper is to provide an overview of the state of the recent evidence regarding use of GFCF diet for treatment of individuals with ASD.

METHODS

Five database providers (PubMed, Web of Knowledge, EBSCO, ProQuest, and WorldCat) were used to search 19 databases yielding a total of 491 articles that were published through February 2015. Peer reviewed articles published between 2005 and February 2015 were included for review if study participants were identified as having ASD and investigated the effects of the GFCF diet on ASD behaviors or the relationship between the diet and these behaviors.

RESULTS

Evaluation of search results yielded 11 reviews, 7 group experimental studies including 5 randomized controlled trials, 5 case reports, and 4 group observational studies published during the last 10 years. These studies represent a marked increase in number of reported studies as well as increased scientific rigor in investigation of GFCF diets in ASD.

CONCLUSIONS

While strong empirical support for the GFCF diet in ASD is currently lacking, studies point to the need for identifying subsets of individuals (e.g., those with documented gastrointestinal abnormalities) who may be the best responders to the GFCF diet. Identifying these subsets is critically needed to enhance rigor in this research area. Until rigorous research supporting use of GFCF diet is reported, clinicians should continue use caution and consider several factors when advising regarding implementation of the GFCF diet for individuals with ASD.

Autism and nutrition: the role of the gut-brain axis

Autism spectrum disorder (ASD) is characterised by deficits in the ability to socialise, communicate and use imagination, and displays of stereotypical behaviour. It is widely accepted that ASD involves a disorder in brain development. However, the real causes of the neurodevelopmental disorders associated with ASD are not clear. In this respect, it has been found that a majority of children with ASD display gastrointestinal symptoms, and an increased intestinal permeability. Moreover, large differences in microbiotic composition between ASD patients and controls have been reported. Therefore, nutrition-related factors have been hypothesised to play a causal role in the aetiology of ASD and its symptoms. Through a review of the literature, it was found that abnormalities in carbohydrate digestion and absorption could explain some of the gastrointestinal problems observed in a subset of ASD patients, although their role in the neurological and behavioural problems remains uncertain. In addition, the relationship between an improved gut health and a reduction of symptoms in some patients was evaluated. Recent trials involving gluten-free diets, casein-free diets, and pre- and probiotic, and multivitamin supplementation show contradictive but promising results. It can be concluded that nutrition and other environmental influences might trigger an unstable base of genetic predisposition, which may lead to the development of autism, at least in a subset of ASD patients. Clear directions for further research to improve diagnosis and treatment for the different subsets of the disorder are provided.

Gastrointestinal dysfunction in children with autism spectrum disorders

Gastrointestinal (GI) dysfunctions are frequently reported by parents of children with autism spectrum disorders (ASD) and have been recently recognized as a comorbid condition. However, the clinical significance of these GI dysfunctions remains to be delineated. This study describes the clinical characteristics, associated comorbid disorders, and endoscopic and colonoscopic evaluation of GI dysfunction in a cohort of 164 children with ASD evaluated at a pediatric neurology practice. Symptoms of GI dysfunction were prevalent: 49% of the children reported one or more chronic GI complaints, 22% exhibited diarrhea, 26% suffered from constipation. Furthermore 13% of the parents reported their children to suffer from bloating and/or being gassy and while 10% of the parents reported vomiting or gastroesophageal reflux problems. Similar rates of GI symptoms were reported among pre-school and school-aged children. Inflammation of the gut was found in 6 of the 12 subjects who underwent endoscopic and colonoscopic evaluations, however clinical symptoms did not predict the results of the evaluation. GI dysfunction was significantly associated with sleep disorders and food intolerance, but not with irritability or aggressiveness. In summary, GI dysfunction was prevalent in this cohort of children with ASD, observations consistent with the reports of parents and other clinicians. We conclude that the GI dysfunction in ASD requires proper evaluation and treatment.