The Role of Epigenetic Modifications in Autism Spectrum Disorder

Study Overview
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Brief Summary
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Autism Spectrum Disorder is a neurodevelopmental disorder characterized by impaired social communication and repetitive or stereotyped behaviors. According to the World Health Organization , the prevalence of Autism Spectrum Disorder is one person in 160.

Detailed Description
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Genetic and non-genetic factors would contribute to the development of autism. However, the molecular mechanisms of ASD are not clear and successful treatments are still under research. Autism Spectrum Disorder can occur due to exposure to environmental pollutants which lead to epigenetic changes like DNA methylation, acetylation and post-translational modifications. However, the role of epigenetic changes in Autism Spectrum Disorder is still debated. Epigenetic mechanisms represent a link through which environmental factors interact with the genetic factors resulting in modification of Autism Spectrum Disorder risk through changes in gene expression. DNA methylation and histone deacetylation are two major epigenetic mechanisms that regulate the gene expression at successive stages of brain development. Brain derived neurotrophic factor is responsible for brain development. Altered BDNF levels and expression may be closely associated with Autism Spectrum Disorder. . Glial fibrillary acidic protein is the hallmark intermediate filament protein in astrocytes, the main type of glial cells in the central nervous system. Interestingly, Glial fibrillary acidic protein is a marker of astroglial activation and the recent data indicated that Glial fibrillary acidic protein could be implicated in the pathophysiology of autism. However, the underlying mechanisms for the role of brain derived neurotrophic factor and glial fibrillary acidic protein in autism spectrum disorder are poorly understood.

Official Title
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The Role of Epigenetic Modifications in Autism Spectrum Disorder Through DNA Methylation

Conditions
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Autism Spectrum Disorder

Intervention / Treatment
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* Genetic: DNA methylation and Real-time Polymerase Chain Reaction Analysis
* Diagnostic Test: Gilliam Autism Rating Scale Arabic version


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - All enrolled children with Autism Spectrum Disorder will be: Exhibit symptoms within the typical triad of autistic traits: communication impairment, social deficits, and ritualistic interests. Drug-naïve. Children with Autism Spectrum Disorder and controls will be 2-6 years old. Exclusion Criteria: The control subjects will also clinically examined by the psychiatrist to exclude any sub-clinical autistic features. Children with Autism Spectrum Disorder and controls will excluded from the study if They receive treatment for any reason. -Endocrinological disease, mental retardation, communication disorder, psychotic disorder, attention deficit hyperactivity disorder and learning disorders seen in the children or their family members.

Ages Eligible for Study
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Minimum Age: 2 Years
Maximum Age: 6 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Autism Cases<br>20 confirmed autism cases will be involved in this study. The autism patients will be diagnosed according to:Gilliam Autism Rating Scale Arabic version: An assessment of the severity of autism using the Gilliam autism rating scale Arabic version: This test was used for diagnosis and assessment of the severity of autistic features for ages 3-22 years. It consists of 56 items, subdivided into 4 subscales: communication, social interaction, stereotyped behaviors, development and total score. Fasting blood samples will be collected from autism children for DNA Methylation-and quantitative Real-time Polymerase Chain Reaction Analysis | Genetic: DNA methylation and Real-time Polymerase Chain Reaction Analysis<br>* Fasting blood samples will be collected from both autism and controls for DNA extraction. Peripheral blood (2ml) will be drawn from the cubital vein intoplastic syringes. Lymphocytes will be isolated from blood samples. We will examine the gene methylation in the peripheral blood lymphocytes of drug-naı¨ve autism patients and control subjects. DNA will be isolated from lymphocytes, purified and processed for bisulfate modification. Bisulfate treatment of genomic DNA will be performed using DNA methylation kit according to the manufacturer´ instructions. Bisulfite treatment of genomic DNA converts cytosine to uracil, but leaves methylated 5'Cytosines unchanged. Quantitative real time Polymerase chain reaction will be used to determine the DNA methylation status of the Brian derived neurotrophic factor and glia fibrillary acidic protein genes using primers specific to the human genes.<br>Diagnostic Test: Gilliam Autism Rating Scale Arabic version<br>* An assessment of the severity of autism using the Gilliam autism rating scale Arabic version: This test was used for diagnosis and assessment of the severity of autistic features for ages 3-22 years. It consists of 56 items, subdivided into 4 subscales: communication, social interaction, stereotyped behaviors, development and total score. The Arabic version has been validated with good reliability and validity and used in many studies before. The lower the scores are, the worse the condition is. The scale will be done by trained and certified psychologist. The protocol and informed consent for this study will be reviewed and approved by the ethics committee at the Faculty of Medicine, Assiut University, Egypt.<br>|
| Control<br>20 age-gender matched typical development children that will be assigned to the normal control group. Control children will be examined by a psychiatrist to exclude any sub-clinical autistic features. Fasting blood samples will be collected from control children for DNA Methylation-and quantitative Real-time Polymerase Chain Reaction Analysis | Genetic: DNA methylation and Real-time Polymerase Chain Reaction Analysis<br>* Fasting blood samples will be collected from both autism and controls for DNA extraction. Peripheral blood (2ml) will be drawn from the cubital vein intoplastic syringes. Lymphocytes will be isolated from blood samples. We will examine the gene methylation in the peripheral blood lymphocytes of drug-naı¨ve autism patients and control subjects. DNA will be isolated from lymphocytes, purified and processed for bisulfate modification. Bisulfate treatment of genomic DNA will be performed using DNA methylation kit according to the manufacturer´ instructions. Bisulfite treatment of genomic DNA converts cytosine to uracil, but leaves methylated 5'Cytosines unchanged. Quantitative real time Polymerase chain reaction will be used to determine the DNA methylation status of the Brian derived neurotrophic factor and glia fibrillary acidic protein genes using primers specific to the human genes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The difference of percentage of DNA methylation of Brain derived neurotrophic factor gene and glial fibrillary acidic protein gene between the two groups | Real Time Polymerase Chain Reaction | one year | 
| The relation between the severity of autistic symptoms and percentage of Brain derived neurotrophic factor gene and glial fibrillary acidic protein gene methylation in Autism cases group | correlation test | one year |