Epigenetic Disorders Paper

“There is no known cause of autism. Current research links autism to biological or neurological differences in the brain – although at this time no gene has been directly linked to autism.”(2, pg 105) Several theories, which exist, link the disorder to environmental and genetic factors. One such research project, performed by Vijendra K. Singh, Ph.D., is based on the concept of “Neuro-immunopathogenesis in Autism.” (1, pg. 26) Doctor Vijendra K. Singh identified his research and resolution as follows:

A lot of various genes appear o be involved in autism spectrum disorder. For some children, autism spectrum disorder can be combined with a genetic disorder such as Rett syndrome or fragile X syndrome. For other genetic changes may make a child more affected to autism or create environmental risk factors. Still other genes may affect the brain progress or the way that brain cells communicate, or they may determine the severity of symptoms. Some genetic problems seem to be innate, while others happen unconsciously. (Mayo clinic staff, 2014)

The study displayed a higher risk for children developing autism if a family member was already affected by the disorder and ten times more likely if a sibling was affected. This study concluded that genetics and environmental factors work together to play a role in the development of autism. Genetics was estimated at 83 percent and environmental influence was estimated at 17 percent. Even though genetics still plays a larger part in the development of autism, environmental factors play a role as well (Large Study Suggests, 2012; Staff, X.S, 2013).

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

Do people have control over their sexual orientation? Many people believe they were born without a choice. In other words, some people believe they were predestined to be homosexual. Homosexuality is defined as the romantic/sexual attraction between members of the same sex. Currently, the cause of homosexuality has not been determined although many speculations have been made. The cause of homosexuality has been disputed for many years. One could argue homosexuality is caused by hormones, genes and/or a type of social deviance. This research paper will offer another alternative. Specifically, it will argue that homosexuality is caused by epigenetics.

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.

Mutations that occur during transcription are also linked to the expression of genes associated with Autism Spectrum Disorder. ASD candidate genes are genes normally related to synapse function, but when the enzyme topoisomerase is inhibited, the genes are not fully expressed4, factoring into the phenotypic expression of Autism. The individuals studied who were affected by ASD had a numerous amount of mutated genes relating to transcription function4. This result illustrates the relationship between transcription and the phenotypic expression 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.

What is epigenetics? Epigenetics to me is the alteration to our genome that we are able to change in not only ourselves but in our children and future generations as well all based on lifestyle habits we live today. After first watching the PBS video on epigenetics, I was astonished on how our ways of life have such a profound effect upon not only our genes but our future generations of children as well. In the video research was conducted on over forty identical twins ages ranging from three to seventy-four, this was to compare the lifestyle habits such as smoking, exercise, and different diets have on an individual. I found it fascinating that when there was comparing the genomes of the elderly Spanish twins compared to the three-year-olds; we were able to see how much of a difference the Spanish twins genome

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,

There has been research in the genetic factors that cause autism. One of these research methods is “family-based and case-control evaluations of candidate genes. These studies have identified numerous candidate loci, most consistently on chromosomes 7q, 15q and 2q.” ( Muhle et al. 2004; and Santangelo and Tsatsanis, 2005, as cited in Landrigan, 2010, pg. 220). Another form of genetic research that has occurred in studying autism is “cytogenetic studies…cytogenetic studies have identified abnormalities on chromosome 15q.” (Muhle et al. 2004, as cited in Landrigan, 2010, pg. 220). While, these genetic research opportunities have found relevant data, only about 8 percent of all autism cases are genetic (Landrigan, 2010). Another cause that has been researched is how environmental factors cause autism. One study found “an increased incidence of autism is reported among children exposed prenatally to thalidomide.” (Rodier, 2002, as cited in Landrigan, 2010, pg. 221). Another chemical that has been found to have a connection with autism is misoprostol. In the U.S. it is used to treat gastric ulcers and, in an instance in Brazil, four out of seven infants that were exposed to misoprostol had autism (Bandim et al. 2003, as cited in Landrigan, 2010, pg. 221). These are only a few examples of research projects and data that has been collected regarding childhood

The autism spectrum is very wide ranging and includes many symptoms. It goes from one or two mild developmental abnormalities all the way up to a person needing a lifetime of care. There are many contributors for autism however, researchers have not found the single cause of autism, and with that, they have not found a cure or accurate prevention methods. It has been found that children who have a sibling with ASD are much more likely to have it, which gives researchers a clue into genetics and how it plays a role in children being born with autism. This paper will discuss the different symptoms of ASD, and what treatments are used to help manage it. A case study will be discussed to show how a child presented with the disorder, and how they were able to live a normal life with the help of various methods of treatment. Genetics will be looked into in terms of siblings and the recurrence rate in families in a scientific study. In another, brain chemistry will be shown in ways that can affect the motor function of those diagnosed with ASD.

Epigenetic characteristics are the process by which your genetic information is changed by environmental influences without an alteration in DNA. Some epigenetic effects occur at the beginning of life as biochemical elements silence methylation, which is the ephemeral of the chemical fragment call methyl group. The details of methylation are not clear to biologist as they are still trying to figure out how it develops and why it modifies gene expression. One interesting discovery to developmentalist is that the known diseases to be genetic (including cancer, schizophrenia and autism) are known to be epigenetic. One example of epigenetics is histone modification, which is increasing or confiscating chemical groups to or from histones.

Epigenetics are those states which are due to the stable and inherited changes which are in the chromosomes but not in the sequence of that DNA.

Epigenetics can be hereditable or environmental factors that affect the expression of genes and lead to changes in gene expression. Unlike genetics, epigenetics does not only have to do with which genes are passed down to the offspring and the DNA sequence. The environmental conditions of the offspring’s parents impact the genes in their eggs and sperms by “switching on” certain genes and “switching of” others (Dowshen). Since the genes expression of the gametes are affect, the phenotypes of the offspring will change. Even in a person’s lifetime, environmental factors such as stress, chemical exposure, and diet can continue to impact gene expression through DNA methylation. During DNA methylation, a methyl group is randomly added to a 5-carbon cytosine ring, making 5-methylcytosine and these groups inhibit transcription. (Cheriyedath). Due the fact that transcription is not possible, the expressing of the genes in that section of the DNA strand will be suppressed. The attachment of the methyl group to DNA is not determined, which means that