Gut Microbiome Characteristics and Neurodevelopmental Functioning in Children With Autism Spectrum Disorder (GAIN-ASD)

June 12, 2026 updated by: Jeevarathinam Thirumalai, Saveetha University

Association Between Gut Microbiome Characteristics and Neurodevelopmental Functioning in Children With Autism Spectrum Disorder: A Multidomain Investigation of the Gut-Motor Axis

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects communication, behavior, sensory processing, and daily functioning. Recent research suggests that the gut microbiome, the community of microorganisms living in the gastrointestinal tract, may influence brain development and function through the gut-brain and gut-motor axes. Alterations in gut microbiome characteristics have been reported in children with ASD and may be associated with differences in neurodevelopmental outcomes.

This observational study aims to investigate the association between gut microbiome characteristics and neurodevelopmental functioning in children with ASD. The study will evaluate multiple domains of functioning, including motor performance, sensory processing, behavior, cognition, sleep, and participation in daily activities. Gut microbiome characteristics will be assessed using stool sample analysis, and neurodevelopmental outcomes will be measured using standardized assessments and validated questionnaires.

The findings of this study may improve understanding of the relationship between the gut microbiome and neurodevelopmental functioning in children with ASD and provide insights into the role of the gut-motor axis in shaping functional outcomes. This knowledge may support future research and contribute to the development of more personalized approaches to assessment and rehabilitation in ASD.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by impairments in social communication, restricted and repetitive behaviors, sensory processing differences, and variable functional abilities across developmental domains. Increasing evidence suggests that the gut microbiome may play a role in neurodevelopment through bidirectional communication pathways linking the gastrointestinal system and the central nervous system. These interactions, commonly described as the gut-brain axis, have been implicated in behavioral, cognitive, sensory, and motor processes. More recently, the concept of the gut-motor axis has emerged, highlighting potential relationships between gut microbial composition and motor functioning.

Several studies have reported alterations in gut microbiome composition among children with ASD compared with typically developing peers. However, existing research has largely focused on autism symptom severity, behavioral manifestations, or gastrointestinal symptoms, while the association between gut microbiome characteristics and broader neurodevelopmental functioning remains insufficiently explored. Furthermore, few studies have examined multiple functional domains simultaneously within a rehabilitation framework.

The present study aims to investigate the association between gut microbiome characteristics and neurodevelopmental functioning in children with ASD. A multidomain assessment approach will be employed to evaluate neurodevelopmental outcomes encompassing motor performance, sensory processing, behavioral function, cognitive functioning, sleep, and participation in daily activities. Gut microbiome characteristics will be assessed through stool sample analysis using established microbiological methods. Neurodevelopmental outcomes will be evaluated using standardized assessments and validated caregiver-reported instruments.

By examining the relationship between gut microbiome characteristics and multidimensional functional outcomes, this study seeks to enhance understanding of the gut-motor axis in ASD and identify potential microbiome-related factors associated with neurodevelopmental functioning. The findings may contribute to the growing body of evidence on microbiome-neurodevelopment interactions and inform future translational and rehabilitation research in children with ASD.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
600

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • India
    • Tamil Nadu
      • Chennai, Tamil Nadu, India, 602 105
        • Saveetha Medical College and Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The study population will consist of children aged 3 to 12 years with a confirmed diagnosis of Autism Spectrum Disorder (ASD) who are receiving care at participating pediatric rehabilitation, developmental, neurology, psychiatry, and autism care centers. Eligible participants will undergo stool sample collection for gut microbiome analysis and multidomain neurodevelopmental assessment, including evaluation of autism severity, gross motor function, sensory processing, cognitive functioning, behavioral function, sleep, participation, quality of life, gastrointestinal symptoms, dietary intake, and anthropometric nutritional status. Written informed consent will be obtained from parents or legal guardians prior to participation.

Description

Inclusion Criteria:

  • Children aged 3 to 12 years
  • Clinical diagnosis of Autism Spectrum Disorder (ASD) according to DSM-5/ICD criteria and confirmed from medical records or specialist assessment
  • Stable clinical status at the time of enrollment
  • Parent/legal guardian willing to provide written informed consent
  • Child able to undergo stool sample collection and neurodevelopmental assessments
  • Parent/caregiver able to complete questionnaires and provide dietary and medical history

Exclusion Criteria:

  • Use of systemic antibiotics, probiotics, prebiotics, synbiotics, or bowel-cleansing agents within the previous 4-12 weeks before stool collection
  • Presence of acute gastrointestinal infection or acute febrile illness at the time of assessment
  • Known chronic gastrointestinal disorders that may independently alter the gut microbiome, such as inflammatory bowel disease, celiac disease, short bowel syndrome, or chronic intestinal malabsorption
  • Major neurological, genetic, or metabolic disorders other than ASD that may independently affect neurodevelopment
  • Current use of medications known to significantly affect gut microbiota or bowel motility, if clinically relevant to your protocol
  • Inability to provide stool sample or complete the required assessments
  • Refusal of consent by parent/legal guardian

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Children With Autism Spectrum Disorder
Children diagnosed with Autism Spectrum Disorder (ASD) who meet the study eligibility criteria. Participants will provide stool samples for gut microbiome analysis and undergo multidomain neurodevelopmental assessment.
Typically Developing Children
Age- and sex-matched typically developing children without a diagnosis of Autism Spectrum Disorder or other neurodevelopmental disorders. Participants will provide stool samples for gut microbiome analysis and undergo neurodevelopmental assessment for comparison with the ASD cohort.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Gut Microbiome Diversity and Composition
Time Frame: Baseline (single stool sample collected at study enrollment)
Gut microbiome characteristics will be assessed from stool samples using 16S rRNA gene sequencing. Primary microbiome outcomes will include alpha diversity indices (Shannon Diversity Index, Simpson Diversity Index, and Chao1 Richness Index), beta diversity measures, and the relative abundance of bacterial taxa. These measures will be used to characterize gut microbial diversity and composition in children with Autism Spectrum Disorder.
Baseline (single stool sample collected at study enrollment)
Indian Scale for Assessment of Autism
Time Frame: Baseline
Autism severity will be assessed using the Indian Scale for Assessment of Autism (ISAA). The ISAA total score ranges from 40 to 200, with higher scores indicating greater autism symptom severity (worse outcomes) and lower scores indicating less severe autism-related impairments (better outcomes). The total score will be used to determine the severity of autism symptoms and examine associations with gut microbiome characteristics.
Baseline

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Gross Motor Function Measure-88 Total Score
Time Frame: Baseline
Gross motor function will be assessed using the Gross Motor Function Measure-88 (GMFM-88). The GMFM-88 evaluates gross motor performance across five dimensions: lying and rolling, sitting, crawling and kneeling, standing, and walking, running, and jumping. Scores range from 0 to 100%, with higher scores indicating better gross motor function (better outcomes) and lower scores indicating poorer gross motor function (worse outcomes). Total scores and dimension scores will be used to evaluate motor performance and its association with gut microbiome characteristics.
Baseline
Gastrointestinal Symptom Severity Score
Time Frame: Baseline
Gastrointestinal symptoms, including constipation, diarrhea, abdominal pain, and bloating, will be assessed using a structured Gastrointestinal Symptom Questionnaire (total score range: 0-100, with higher scores indicating greater gastrointestinal symptom severity). Stool consistency will be assessed using the Bristol Stool Form Scale (BSFS), a 7-point scale ranging from Type 1 (separate hard lumps, indicating severe constipation) to Type 7 (entirely liquid stool, indicating severe diarrhea), with higher scores reflecting looser stool consistency.
Baseline
Strengths and Difficulties Questionnaire Total Difficulties Score
Time Frame: Baseline
Emotional and behavioral difficulties will be assessed using the Strengths and Difficulties Questionnaire (SDQ) Total Difficulties Score. The total difficulties score ranges from 0 to 40, with higher scores indicating greater emotional and behavioral difficulties (worse outcomes) and lower scores indicating fewer difficulties (better outcomes).
Baseline
Patient-Reported Outcomes Measurement Information System Sleep Disturbance Scale Score
Time Frame: Baseline
Sleep disturbance will be assessed using the Patient-Reported Outcomes Measurement Information System Sleep Disturbance Scale (PROMIS Sleep Disturbance Scale). The scale evaluates perceived sleep quality, sleep difficulties, sleep satisfaction, and sleep-related concerns. Scores range from 8 to 40, with higher scores indicating greater sleep disturbance (worse sleep outcomes) and lower scores indicating better sleep quality. Associations between sleep disturbance and gut microbiome characteristics will be examined.
Baseline
Participation Questionnaire for Preschoolers With Autism Score
Time Frame: Baseline
Participation will be assessed using the Participation Questionnaire for Preschoolers with Autism (PPA). The questionnaire evaluates participation in home, preschool, community, play, and social activities. The total score ranges from 0 to 100, with higher scores indicating greater participation in everyday activities (better outcomes) and lower scores indicating reduced participation. Associations between participation outcomes and gut microbiome characteristics will be examined.
Baseline
Sensory Experiences Questionnaire Total Score
Time Frame: Baseline
Sensory processing will be assessed using the Sensory Experiences Questionnaire Version 2.1 (SEQ-2.1), a caregiver-reported measure designed to evaluate sensory experiences in children with Autism Spectrum Disorder. The questionnaire assesses sensory hyperreactivity, hyporeactivity, and sensory-seeking behaviors across multiple sensory modalities. The total score ranges from 0 to 145, with higher scores indicating greater sensory processing difficulties (worse outcomes) and lower scores indicating fewer sensory processing difficulties. Associations between sensory processing outcomes and gut microbiome characteristics will be examined.
Baseline
PROMIS Parent Proxy Cognitive Function Score
Time Frame: Baseline
Cognitive functioning will be assessed using the Patient-Reported Outcomes Measurement Information System Parent Proxy Cognitive Function Measure (PROMIS Parent Proxy Cognitive Function Measure). The instrument evaluates caregiver-reported difficulties related to attention, memory, concentration, learning, and thinking abilities in children. Scores are reported as standardized T-scores (mean = 50, standard deviation = 10), with higher scores indicating better perceived cognitive functioning (better outcomes) and lower scores indicating poorer cognitive functioning (worse outcomes). Associations between cognitive function and gut microbiome characteristics will be examined.
Baseline
Dietary Intake Score
Time Frame: Baseline
Dietary intake will be assessed using parent proxy-reported 24-hour dietary recalls collected on 2-3 non-consecutive days, including at least one weekend day, using the multiple-pass recall method. Information on daily energy intake (kcal/day), macronutrient intake (g/day), dietary fiber intake (g/day), and consumption of key food groups (servings/day) will be recorded. A supplementary Food Frequency Questionnaire (FFQ) will assess the habitual consumption of fruits and vegetables, whole grains, fermented foods, sugar-sweetened beverages, and ultra-processed foods. Composite Healthy Diet Score and Unhealthy Diet Score will be derived to characterize dietary patterns, with higher Healthy Diet Scores indicating healthier dietary patterns and higher Unhealthy Diet Scores indicating less healthy dietary patterns. Dietary intake variables will be used as covariates in analyses examining associations between gut microbiome characteristics and neurodevelopmental functioning in children with
Baseline
Pediatric Quality of Life Inventory Total Score
Time Frame: Baseline
Quality of life will be assessed using the Pediatric Quality of Life Inventory (PedsQL). The instrument evaluates physical, emotional, social, and school functioning in children. Scores range from 0 to 100, with higher scores indicating better health-related quality of life (better outcomes) and lower scores indicating poorer health-related quality of life (worse outcomes). Associations between quality of life and gut microbiome characteristics will be examined in children with Autism Spectrum Disorder.
Baseline
Anthropometric Nutritional Status Score
Time Frame: Baseline
Anthropometric nutritional status will be assessed using standardized measurements of height (cm), weight (kg), and body mass index (BMI; kg/m²). Age- and sex-specific z-scores for weight-for-age, height-for-age, BMI-for-age, and weight-for-height (where applicable) will be calculated according to the World Health Organization (WHO) Child Growth Standards and Growth Reference charts. For z-score indicators, a value of 0 represents the WHO reference population median, positive values indicate measurements above the reference median, and negative values indicate measurements below the reference median. Nutritional status categories, including undernutrition, normal nutritional status, overweight, and obesity, will be determined using WHO classification criteria. Associations between anthropometric nutritional status and gut microbiome characteristics will be examined in children with Autism Spectrum Disorder.
Baseline
Body Mass Index-for-Age Z-Score
Time Frame: Baseline
Body mass index (BMI) will be calculated as weight (kg) divided by height squared (m²). BMI-for-age z-scores will be derived using World Health Organization (WHO) age- and sex-specific growth references. A z-score of 0 represents the WHO reference population median, positive z-scores indicate BMI values above the reference median, and negative z-scores indicate BMI values below the reference median. BMI-for-age z-scores will be used to evaluate nutritional status and examine their association with gut microbiome characteristics and neurodevelopmental functioning.
Baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Saveetha University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 9, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 9, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 15, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 12, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 079/06/2026/ISRB/FSR/SIBMS

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data (IPD) may be shared upon reasonable request following publication of the study findings, subject to institutional policies, ethical approval requirements, participant confidentiality protections, and applicable data-sharing agreements. A final decision regarding IPD sharing will be made after completion of the study and in accordance with institutional and regulatory guidelines.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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