Genetic And Epigenetic Influences On Autism Spectrum Disorders : A Role For The Methyl

The first major effects of epigenetics on genes can be seen in the role of DNA methylation in mammalian epigenetics. DNA methylation provides a method of gene control in an organism, where it assures proper gene expression, as well as silencing of genes within cells, it does this through the manipulation of chromosome architecture, where it affects the packaging of the DNA by the binding of a methyl group to cytosine (Kullis & Esteller, 2010). The effects of this can

Autism is a rare disease that can be characterized by a “neurodevelopmental disorder categorized by the inability to relate to and perceive the environment in the realistic manner.” (Anthes, 1997) The signs of autism are mainly found in infants to young children usually between the ages of newborn to two years. The main symptoms that are discussed are “impairment in social interaction fixation of inanimate objects, inability to communicate normally, and resistance to changes in their daily routine.” (Anthes, 1997) Autism is a very understood disease but one thing most people do not know is that autism not only effects a child’s life mentally and physically, it also effects their social ability to have friends, play normally and even grow up

Autism spectrum disorders are a class of developmental disorders that impair social skills, behavior, and communication (Center for Disease Control). ASDs are considered ‘spectrum’ disorders because each patient has a unique experience in the nature and severity of their symptoms (Center for Disease Control). Under the umbrella of ASDs, there are three types of disorders, including Autistic disorder, Asperger Syndrome, and Pervasive Developmental Disorder Not Otherwise Specified (Center for Disease Control). Autistic disorder is the most severe of the three, and patients exhibit significant problems with language, communication, and behavior (Center for Disease Control). Furthermore, people with Autistic disorder often have some intellectual impairment (Center for Disease Control). Asperger Syndrome is a milder form of autistic disorder where patients have some developmental delays, but their language and intellect are not affected (Center for Disease Control). The mildest of the ASDs is the pervasive developmental disorder. These patients usually don’t meet all of the criteria for autistic disorder, but do show some signs of social and communication problems (Center for Disease Control). The number of children diagnosed with ASD is growing, and currently 1 in 88 children fall somewhere on the spectrum (Mari-Bauset et al., 2013). Boys are four times more likely than girls to have autism, and while the exact cause of these disorders is unknown, both genetic and

Autism is characterized as a neurodevelopmental disorder that affects social interactions, nonverbal and verbal communication, and restricted and repetitive behavior. On a global scale, autism was estimated to affect 21.7 million people in 2013, and the number continues to rise as time persists. Children are often diagnosed while they are infants, usually in the first two years of life, when parents notice odd behaviors such as assembling toys or stacking of objects. It is not yet well understood how autism occurs, but we do know that autism affects information processing in the brain by changing the way nerve cells and their synapses connect and organize. Autism is one of the three disorders that make up the Autism Spectrum, the second is

Five other gene disorder that contributes to autism are (1) "EN2 (Engrailed 2) involved in cerebellum development. (2) GABR (Gamma Amino Butyric Acid Receptor) regulates brain cell migration. (3) OXTR (Oxytocin Receptor) participating in the response to stress and social skills. (4) RELN (Reelin) involved in neuronal migration in the developing brain. (5) SLC6A4, a serotonin transporter gene” (Johnson, Giarelli, Lewis, & Rice, 2013). As a result of all the researches done several chromosomal loci have been shown to be linked to Autistic Spectrum disorder including those at 2q24-2q31, 7q22-7q31, 7q34-7q36, and 17q11-17q21. Structural chromosomal changes involving deletions and duplication at 7q11, 15q11-15q13, 17p11.2, 22q11.2, and 22q13 have also been associated with forms of autism. However, the most common chromosomal abnormalities currently associated with autism include the fragile X mutation, other sex chromosome abnormalities, and abnormalities of 15q11-q13. “Evidence has shown that duplications of 15q11–q13 have led to higher risks of Autism Spectrum Disorder and developmental and cognitive deficits” (Flashner, Russo, Boileau, Leong, & Gallicano, 2013). Chromosome 15q11-q13.1 region is subject to genomic imprinting, which is an epigenetic process that results in monoallelic gene expression. Duplications lead to autism and are usually maternal in origin. Deletion of the maternal allele of chromosome 15q11-q13 cause Angelman syndrome (AS) a neurodevelopmental disorder

Park, H. R., Lee, J. M., Moon, H. E., Lee, D. S., Kim, B.-N., Kim, J., … Paek, S. H. (2016). A Short Review on the Current Understanding of Autism Spectrum Disorders. Experimental Neurobiology, 25(1), 1–13. http://doi.org/10.5607/en.2016.25.1.1

Chapter 1 focuses on autism, Pervasive Developmental Disorders (PDDs) and other Autistic Spectrum Disorders (ASDs). Described in 1943 by Dr. Leo Kanner, autism (also known as autistic disorder, childhood autism, or infantile disorder) is one of the PDDs along with Rett's disorder, Childhood Disintegrative Disorder (CDD) referred to as Heller's syndrome, Asperger disorder, and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). Rett's is a rare genetic abnormality affecting brain development in girls. There are treatments available, but there is no known cure. Asperger disorder affects an individual's ability to socialize and communicate effectively. Individuals with Asperger disorder may be socially awkward and have a compulsive

This paper plans to focus on autism spectrum disorder and how epigenetics contributes to the development of the disease. ASD is comorbid with other neurodevelopmental diseases including Rett Syndrome, Fragile X, Prader-Willi, and Angelman. These diseases have frequent, identifiable symptoms such as coloboma of the eye, heart defects, atresia of the nasal choanae, retardation of growth and or development, genital and or urinary abnormalities, and ear abnormalities and deafness. The definition of stochastic is to have a random probability distribution or pattern that may be analyzed statistically but may not be predicted precisely.

Neurological disorders are complex in nature and often the least understood. Given the recent boom in imaging technology and other diagnostic methods, it is now possible to see more clearly into the scope of neurological development and accurately determine the etiology of these diseases. One of such disorders is Autism; a multifactorial condition impairing normal brain development. It affects many aspects of development, including social behavior, cognitive ability and communication skills1 and is commonly diagnosed in children before the age of three1. The symptoms of this condition can vary greatly between individuals; hence its classification as a spectrum disorder. Asperger syndrome, Rett syndrome and pervasive

Symptoms typically are apparent before children turn 3 years old. (7). When individuals are born as an identical twin or have first degree relatives who have autism, they are automatically at a higher risk for developing it themselves. Other risk factors include immune dysregulation, altered short chain fatty acids, genetic mutations involving the metabolism of vitamin D, infections, teratogens, or antibodies maternally. For every 68 boys who are born, 1 will likely have autism, as boys are about five times more likely to present with autism than girls are. (3). When the brains of patients with Autism Spectrum Disorder are studied and compared with those who do not have the disorder, there are obvious differences. In the Autism Spectrum Disorder brain, there are alterations to the striatal circuits, a dysfunction in canonical neural circuits, and an abnormal basal ganglion connectivity. These striatal dysfunctions of the brain are evidence as to why abnormal behaviors occur in autistic patients (repetitive grooming, stereotypic motor routines, and deficits in social interaction and decision-making). There may even be evidence that links genetics to these specific neural circuits. (8). When MRI’s are taken on young autistic patients, the hyperplasia of their cerebral cortex can often be seen. Because the frontal and temporal lobes are important for social functioning and language development, these anatomical anomalies are likely to underlie the pathophysiology of autism.

Epilepsy and Autistic spectrum disorders (ASDs) are both genetic disorders stemming from multiple possible origins. Both disorders share multiple similarities, including cell growth, synapse development and function, and regulation of gene transcription. An incorrect or non-functioning synaptic protein causes many mutations within genetics that predispose one to both ASD and epilepsy. In addition, a recent study found that epilepsy was diagnosed in some form in 44% of children with ASD. Conversely, 54% of adolescents with epilepsy are later diagnosed with a form of ASD.

The autism spectrum disorder (ASD) has a multitude of risk factors such as: genes, environmental chemical exposure, maternal factors, drug interactions, including potentially unidentified variables. These factors may act independently and/or through complex interactions to produce autism (Dietert et al., 2011). There is a growing concern with ADS due to the increased prevalence. Autism is a lifelong chronic disorder that appears to be connected to a host of comorbidities. This fact can be used to make the case that the public health strategy has not been effective in reducing this epidemic (Dietert et al., 2011). Currently there is no one environmental factor that has been identified that can account for ASD epidemic, and there appears to be more risk factors regularly identified.

When DNA and histones are modified, we get epigenetic marks that are considered enduring within singular cells during their development, and which are also hereditary across cell divisions. Since the design of neurons via epigenetic mechanisms is essential to the neural development, any alteration or disruption in the process may lead to an assortment of neurodevelopmental disorders which can include autism spectrum disorders (ASDs). Evidence that has recently come up proves that in the case of ASDs, an altered epigenetic landscape exists, which indicates that epigenetic mechanisms play a critical role in their pathogenesis. This paper discusses how epigenetic dysregulation plays a significant role in selected neurodevelopmental disorders,

The research of epigenetics has evolved from the twentieth century from two scientists including Conrad H. Waddington and Ernst Hadorn who combined genetics and biology. There was an interest in this study in the 1990s. Research has evolved trying to figure out the changes caused by epigenetic mechanisms. This field is growing as researchers are unraveling environmental and lifestyle influences on genes (Epigenetics, n.d.). This paper will discuss differences in epigenetics and genetics, current research of epigenetics, and diseases associated with epigenetics.

Temple Grandin, a doctor in the field of animal sciences who suffers from Autism, once said, “People are always looking for that single magic bullet that will totally change everything. There is no single magic bullet.” Autism Spectrum Disorder (ASD) is a general term for a group of complex disorders of brain development. The Autism Spectrum can be split into many subtypes, including Childhood Disintegrative Disorder, Asperger’s Syndrome, and Pervasive Development Disorder- Not Otherwise Specified (PDD-NOS). Starting from an age as young as infancy, symptoms of Autism may be conveyed. Repetitive behavior, any loss of speech or social skills, and attachment to parents are three of the many symptoms expressed by children with Autism (“What