Abstract: In this paper I briefly will summarize current research articles and journals of authors in reference to the genetics of autism spectrum disorder.

 

 Outline of how paper should be constructed:

 

I. Introduction

II. Background on Autism Spectrum Disorder

III. Genetics of Autism Spectrum Disorder

IIII. Neuroscience of Autism Spectrum Disorder

V. Summary of Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a cluster of developmental disorders whose characteristics include adverse and pervasive impairments in social interaction and communication as they emanate from the brain (Sanchack & Thomas, 2016). The disorders include Asperger syndrome (AS), childhood disintegrative disorder, pervasive developmental disorder and Autistic Disorder (Barna, 2017). There are the specific set of symptoms that tend to display in an individual with any of these disorders. Among these symptoms are Impaired social and communication interactions, restricted set of thinking and interests, and finally repetitive movements and behavior. The reason behind the occurrence of these symptoms in people with ASD cannot yet be explained, but most of them usually appear at the age of three in an individual (Rodger, 2014).

Background on Autism Spectrum Disorder

Autism is a term that was introduced in the psychiatric literature by a Swiss psychiatrist by the name Eugen Bleuler in 1911. The term was coined from the word autos Greek for self. The word describes the extreme antisocial and self-obsessive behavior observed in children. Ever since, efforts have been made to recount the existence of the disorder historically through observation of the symptoms. There have been reports of features of autism from as early as the mid-1700s (Barna, 2017). However, it was not until 1943 when Leo Kanner from John Hopkins Hospital published the first ever case study of autism referring to it as a medical condition. In 1944 Hans Asperger, a scientist from Australia described a disorder which had similar symptoms with autism, however milder. The disorder was referred to as Asperger’s syndrome. More work continued to be done on observing and recording various aspects of autism. Bernard Rimland in 1964, published his work on autism in a book he called Infantile Autism: The Syndrome and Its Implications. In this manuscript, Rimland argues that autism emanates from the brain and not just a physiological condition. The main feature of the disorder being inability to develop normal relationships with people and repetitive behavior, Donald Baer, Todd Risley and Montrose Wolf in 1968 published a paper on a behavioral therapy that would focus on minimizing repetitive behavior in children and developing social skills (Lubetsky, Handen & McGonigle, 2017).

More modern work has been published on the disorder among them being that of Professor Uta Frith. In two of her works as late as 1991, Frith has made a significant contribution in recording historical autism-like characteristics observed in Europe. Among these were two cases, that of France and the other from Scotland both of which took place in the eighteenth-century. From the case of the man from Scotland, the story goes that the man appeared in court in regards to his mental ability to contract a marriage. In Frith’s observation of this case, the man displayed that would be today classified as similar to autism which included, abnormal gazing, echolalia, poor social relationships, repetitive language, collecting objects and poor mannerisms. The other case of France was recorded by a physician who treated a twelve-year-old boy who was in the woods. In the recorded data, the boy could not speak but instead produced bizarre noises, he had poor social skills and showed impulsive and overactive traits. Frith observed in her work that the symptoms would be classified as autism as they are the same one people with what has been diagnosed in the modern-day autism display (Lubetsky, Handen & McGonigle, 2017).

Andrew Wakefield from Britain and twelve other researchers published a paper in 1998 in The Lancet, linking autism to childhood vaccination for rubella, measles, and mumps. As a result, many parents in the U.S and Britain resorted to denying their children the vital vaccines hence putting them at risk of contracting the diseases. Scientist found flaws in the paper and finally in 2007 ten of the co-authors denounced their findings. Consequently, The Lancet retracted the paper in 2010. The same year the British Medical Council revoked Andrew’s medical license following The Lancet decision. There have been studies over the years, and no causal link has been found between childhood vaccination and autism. Many scientists have termed Wakefield’s research as a cause of fear of childhood vaccination and a drag on the autism research (Barna, 2017).

An array of researches have since been done to not only define the disorder but also to try and find the cause, the treatment, and management of the disorder. Through the research, it is quite clear who between men and women are more prone to this among many other elements.

Genetics of Autism Spectrum Disorder

In discussing the genetics of Autism Spectrum Disorder contrasting syndromic and non-syndromic is crucial as it elaborates deeper on the aspects.

Syndromic ASD

The Syndromic ASD consists of identifiable syndromes with genetic causes that are known. They may include but not limited to Fragile-X syndrome, and Tuberous Sclerosis. Syndromic ASD is characterized by dysmorphic features like anatomical brain abnormalities, seizures, chromosomal abnormalities intellectual disability (ID). It is approximated that 10% of children evaluated for Autism Spectrum Disorder are found to be having a medical condition with a genetic lesion such as tuberous or Fragile X. 10% more are found to have copy number variation related to ASD or have a chromosomal structural abnormality (Lubetsky, Handen & McGonigle 2017).

According to data compiled by Lubetsky, Handen & McGonigle (2017), of 15q duplication-Angelman syndrome, the number of individuals with the syndrome and have ASD is more than 40% and that of patients with ASD and have the signs is between one and two percent. The Gene associated with this syndrome is UBE3A. In 16p11 deletion syndrome, the number of patients with this syndrome and have ASD, is high while the number of individuals with an ASD that have the syndrome is approximately 1%. The Gene associated with this syndrome is however unknown. 22q deletion as a syndrome related to the SHANKS Gene and the number of patients with this syndrome and high ASD is high. There is a rare occurrence in patients with an ASD and have the syndrome (Lubetsky, Handen & McGonigle 2017).

From recent genome-wide scans, it is apparent that a little chromosomal duplication or deletion could be the origin of ASD. Through various studies, it is estimated that at least 2% of familial and10% of sporadic ASD may be due to de novo copy number variation (CNV). The list of know ASD- related CNVs may increase with the advancement in microarray technology (Buxbaum & Hof, 2013).

Non-syndromic ASD

The non-syndromic ASD of cases with or without identifiable duplication or deletion in the DNA. The microgenetic alterations are found within the abnormal chromosomal regions in the syndromic ASD thus the link between syndromic and non-syndromic. People with the non-syndromic ASD are most likely to be male. The ratio of female to male on the prevalence of non-syndromic ASD IS 1:4 (Lubetsky, Handen & McGonigle 2017).

The distinction between syndromic and non-syndromic ASDs is starting to thin in that the genes associated with non-syndromic ASD are found within chromosomal regions or abnormal chromosomes which result in syndromic ASD.

Neuroscience of Autism Spectrum Disorder

In 1943 when Leo Kanner published his work on Autism, he noted that out of 11 of the patients her diagnosed with autism, five of them had a brain enlargement from the ordinary which triggered the study of the circumference of the brain. The study conducted during the time yielded little to no results as there were no techniques to better the study. However, with technological advancement there came the magnetic resonance imaging (MRI) which allowed the study of the brain structure and function of an individual with ASD (Buxbaum & Hof, 2013).

Study of the brain prior the introduction of MRI suggested that there was a significant process in age-dependent brain growth abnormality in an individual with autism. There have been studied implying that the size of the brain of a young child with autism increased by 5-10%. Year of study in this area has consistently suggested that there has been a correlation between an increased brain volume and the severity of autism symptoms. The child’s brain size returns to normal or smaller by the time they are adolescents heading to adulthood. Various studies have also suggested that several brain regions play a role in ASD and these areas may increase or decrease in size compared to those children without the ASD (Buxbaum & Hof, 2013)..

Summary of Autism Spectrum Disorder

Autism Spectrum Disorder is a condition that is not physiological but emanates from the brain. Various studies have shown that variation in the size of the brain and some parts of it that affect the way of life are the most crucial in determining the causal elements. It is also apparent that gene duplication and deletion of de novo copy number variation can cause various syndromes associated with ASD. However, as much as individuals with the disorder have traits like repetitive patterns of interests and behavior, social and communication restrictions, they could lead a normal lifestyle. The lifestyle could be achieved through proper management from a tender age through activities behavior therapy for 25 hours a week, contemporary alternatives life fine art or medicine (Sanchack & Thomas, 2016).