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society, many individuals are under the impression that the primary cause of autism is vaccinations. Even though many believe this to be true, there is no scientific evidence to back up their thoughts, proving their beliefs to be invalid. So, you may be asking a couple of questions right now such as, "Why is it that so many people have associated autism with vaccinations," or "If vaccinations do not cause autism, then what does?" Numerous scientists would have answered such questions by providing an explanation that involves genetics; however, many are beginning to question how much genetics, which was previously recognized as the only contributing factor to autism, actually affects autism. Instead, these scientists that question the reliability of a genetic answer believe that environmental factors are the sole cause of autism. Many are beginning to believe this because of the sudden dramatic increase in autism rates that has recently occurred. After researching the viewpoints of both sets of scientists, those who believe genetic causes are more influential and those who believe environmental causes are more influential, I have been led to believe that the true contribution to autism is a combination of both genetic factors and environmental factors. In order for one to make their own decision about the real cause, it is important for them to become educated about autism by learning about its background information, its symptoms, and of course, its genetic and environmental influences.
In order for one to make their own decisions
about the causes of and begin to comprehend autism (This part doesn't make sense..) it
is important for them to begin by learning the basics: background information such as the chronological history, its different types, and its prevalence in recent years. The chronological history of autism began in 1908 when the term "autism" was first used by a Swiss psychiatrist named Eugen Bleuler. (Anonymous d 2013, 1
, Mandal 2013, 1
) However, Bleuler's use of this term is not the same as today's usage; instead, Bleuler used "autism" to describe a schizophrenic patient who never interacted with other people and was withdrawn in his own world. (Mandal 2013, 2
) Bleuler's usage of his newly formulated word makes sense if dissected to the Greek etymologies; the prefix "autos", translates to "self" in modern English, and "ismos" translates to "action or state of being." So, if these two etymologies are put together, they produce a word, autism, meaning "the state of being absorbed by one's self." (Anonymous d 2013, 2
) Although the term "autism" first showed up in 1908, it was not ever recorded to be used again in an important situation until much later by a child psychiatrist named Leo Kanner, who, in 1943, performed a study involving 11 children. The children that he studied that he called autistic each shared similar features which included having troubles with socially interacting, having the five senses be extra sensitive, having difficulty adjusting to changes in a normal routine, having great memory, and having echolalia, or involuntarily repeating words or phrases said by someone else. (Mandal 2013, 3
) So, Kanner was the first to classify individuals who are autistic as we know it today. Even though Kanner's use of the word is what is (Remove what is.)
widely used by society today, autism was not recognized as its own disorder until the 1960's. (Anonymous d 2013, 3
) So, the most important events of the chronological history of autism include the first use of the word by Bleuler in 1908, the study performed by Kanner in 1943 that defined autism as its known today, and the recognition of autism being its own disorder in the 1960's.
Since the initial discovery of autism, or at least what it is known as today, in 1943, five different kinds have been established. Before one learns about these different kinds, it is first important for them to understand that autism itself is not a single disorder. Instead, autism is a spectrum of disorders that are greatly related because of their core symptoms. (Smith, et. al. 2012, 1
) This is why autism's disorders are technically known as "autism spectrum disorders." The five autism spectrum disorders are autistic disorder, Asperger's syndrome, pervasive developmental disorder (PDD), Rett syndrome, and childhood disintegrative disorder. (Anonymous e 2013, 1
) Although all of these disorders are all autism spectrum disorders, each one has symptoms that differ in severity.
One of the main reasons scientists are beginning to believe that environmental factors have the largest influence on autism spectrum disorders,
is its rising prevalence in recent years around the world. (A?) One
decade after these disorders were considered to be their own disorders in the 1960's, they were present in 1 in every 5,000 individuals worldwide, meaning approximately 0.02% of people people
were autistic. During the next decade, or more specifically, 1985, autism spectrum disorder rates doubled from that of the previous decade, and 1 in every 2,500 individuals were
affected worldwide (0.04%). Then, in 1995, the rates increased five-fold from 1985, and 1 in every 500 individuals were
affected (0.2%). As, of 2009 autism rates were
extremely high, affecting 1 in every 110 individuals worldwide, meaning about 0.91%. (Anonymous f 2012, 1
) Additionally, the national rates in the United States are drastically higher than the average international rates. In fact, the United States autism(autistic)
rates have increased from affecting less than 3 per 10,000 individuals in the 1970's,
to affecting more than 30 per 10,000 individuals in the late 1990's. (Blaxill 2004, 1
) Taking into account,
all of autism spectrum disorder's important background information such as chronological history, different types, and prevalence in recent years is extremely important for one grasp the concept of what many think is just "autism" truly is.
For one to fully understand what autism spectrum disorders actually are and what are their affects on individuals
, it is crucial to understand the symptoms. All autism spectrum disorders have three core symptoms; however, depending on the type of disorder, the severity of each of these three symptoms differs. Autism spectrum disorders specifically contain the word "spectrum" because its core symptoms can differ so greatly, being on "one of the spectrum or the other." The three main symptoms of all autism spectrum disorders are difficulty socially interacting with others, issues with communicating verbally and non-verbally, and having repetitive behaviors or having obsessive interests. (Schoenstadt 2008, 1
) First, one with an autism spectrum disorder will encounter difficulties with social interaction such as enormous struggle learning to develop nonverbal skills like eye-to-eye contact, facial expression, and body language. Because of this difficulty with social interaction, the learning process is also made much more difficult, for much less is conceived from whoever is instructing . (Schipul, et. al. 2011, 6
) Behavioral studies have proven that procedural learning, learning by performing (practicing) and perceptual learning, learning by being instructed, were both impaired in those with autism spectrum disorders. (Schipul, et. al. 2011, 7
) Additionally, those with autism spectrum disorders may fail to make friends with those their age and lack empathy, failing to understand the pain and sorrow of others. (Anonymous a 2010, 1
) Difficulty with social interaction can be recognized in an individual as early as when they are an infant, for they may be unresponsive to the presence of others or focus so much on one item for long periods of time that they completely exclude everything else around them. (Schoenstadt 2008, 2
Second, one who has an autism spectrum disorder will have problems with communicating verbally and non-verbally. Such problems with communication include complications with just learning to talk, difficulty starting a conversation, struggling to continue a conversation that has already begun, and echolalia, the constant repeating of a word or phrase previously heard. Also, communication is so much of an issue that 40% of individuals with an autism spectrum disorder never speak. (Anonymous a 2010, 2
) Furthermore, they have difficulty making sense of what others are thinking or feeling because they are incapable of understanding social clues like tone of voice. (Schoenstadt 2008, 5
The last core symptom of autism spectrum disorders is repetitive behaviors or obsessive, limited interests. One limited interest is an unusual focus on a piece of a whole object as opposed to the whole object itself. For example, one with an autism spectrum disorder may direct all of their attention to the wheels of a toy car instead of the actual toy car. Another limited interest is a preoccupation with a certain topic. In addition to limited interests, an individual with an autism spectrum disorder has repetitive behaviors and may need to consistently follow the same routine day after day. (Anonymous a 2010, 3
) They may also engage in repetitive motions like rocking and twirling or engage in self-abusive behavior like biting themselves and banging their head against something. (Schoenstadt 2008, 6
) In addition to the three core symptoms of autism spectrum disorders, experiencing difficulty socially interacting with others, having issues with communicating verbally and non-verbally, and having repetitive behaviors or having obsessive interests, many individuals have altered sensitivity. For example, most children with an autism spectrum disorder have reduced sensitivity to pain and are very sensitive to sensory stimuli such as sound or touch. (Schoenstadt 2008, 9
Although understanding the symptoms of all autism spectrum disorders in general is extremely important, of equal importance in understanding the variations in symptoms of specific disorders. Overall, there are five of these autism spectrum disorders; these include autistic disorder, Asperger's syndrome, pervasive developmental disorder, Rett syndrome, and childhood disintegrative disorder. Autistic disorder is an autism spectrum disorder that has all three core symptoms: problems with social interactions, problems with communication, and limited interests. (Anonymous e 2013, 2
) The second disorder is Asperger's syndrome, which has problems with social interactions, a small struggle with language (communication), and a limited scope of interests. (Anonymous e 2013, 3
) One with pervasive developmental disorder, the third disorder, experiences only some of the symptoms of a true autism spectrum disorder, but not all. So, pervasive developmental disorder does not technically fall under the autism spectrum disorder category, but since those who have it cannot be labeled as any of the other four disorders, they are still considered autistic. (Anonymous e 2013, 4
) The fourth disorder, Rett syndrome, is known to cause children to start developing normally but then begin to lose communication skills and social skills; then by age one to age four, children start to have repetitive hand movements instead of purposeful use of the hands. (Anonymous e 2013, 5
) The final disorder, childhood disintegrative disorder, causes children to develop normally for at least two years, but then they lose two or more of their acquired skills in areas of language, socializing, play, bowel or bladder control, and coordination. (Anonymous e 2013, 6
, Anonymous g 2013, 1
) All in all, autism spectrum disorders vary greatly in many aspects but always have the same general symptoms.
In order for one to make their final decision of whether autism spectrum disorders mainly come from genetic influences or environmental influences, it is vital for them to examine studies performed that seek the main cause. Studies performed that seek the main cause of autism spectrum disorders through genetics have identified copy number variants (CNV's), microscopic deletions or duplications in the DNA, as the main cause of autism. (Morrow, et. al. 2008, 5
) De novo CNV's are microscopic deletions or duplications in offspring that resulted from mutations in gametes of the parents. (Anonymous b 2012, 4
) De novo CNV's have been credited with causing autism spectrum disorders for two reasons. First, de novo CNV's are very prevalent in autism spectrum disorder patients, being seen in 8% of their genes as opposed to only 2% in non-autistic genes. De novo CNV's are also credited because they commonly show up in genes such as CHD8, SCN2A, KATNAL2, and NTNG1 and mutate them. (Mitchell 2012, 5
) Although the name of these genes sounds complex, understanding the function of them is rather simple. These genes code for proteins involved in brain functions, such as growing nerves and making physical connections in the brain. (Mitchell 2012, 6
) So, if any of these proteins were coded for incorrectly because of the de novo CNV, it is obvious as to why they would lead to struggle in activities involving the brain like socializing and communication, two core symptoms; however, even though a connection has been noticed, how the specific de novo CNV's observed in these genes directly cause autism spectrum disorder symptoms is still not very clear. (Mitchell 2012, 7
) Additionally, only a handful of CNV's have been linked with autism spectrum disorders, but there is a possibility that hundreds or even thousands of mutated genes that actually are linked. (Mitchell 2012, 8
There are two factors which increase the prevalence of CNV's in offspring, and therefore, can lead to autism spectrum disorders. First, the prevalence of de novo CNV's in an offspring are increased as the age of father is increased because sperm mutations are more likely to occur. In fact, studies performed suggest that fathers over the age of forty are five times more likely to have a child with autism. (Mitchell 2012, 2) The reason that paternal age, the age of the father, affects the chance of a sperm mutation is because sperm cells continue to divide in men throughout their lifetime, and as a result, the chance of mutation increases. (Mitchell 2012, 3) Second, the chances of CNV's in an offspring is increased if the offspring's parents share ancestors. (Morrow, et. al. 2008, 1
) As of now, these are the only genetic relations which have been scientifically proven to be linked with autism spectrum disorders.
Just like there are studies focused on the genetic links to autism spectrum, there are studies focused on environmental links to autism. First, however, it is important to understand the truth about one of the most misunderstood "causes" of autism spectrum disorders: vaccinations. Many individuals believe that vaccinations cause children to develop autism spectrum disorders because of a preservative it contains called thimerosal, which contains a mercury. (Gelman 2013, 1
) Individuals believed too much of the chemical in too short of a time-frame could potentially impact brain development. (Gelman 2013, 2
) However, research has proven that babies excrete thimerosal too quickly for it to build in in dangerous amounts, and thimerosal was removed by most vaccines in 2001; therefore, there should be no question of whether or not vaccines cause autism spectrum disorders now. (Gelman 2013, 3
) Possible factors that cause autism spectrum disorders are maternal birth abroad (28% increase), diabetes during pregnancy (100% increase), uterine bleeding during pregnancy(81% increase), and exposure to toxic chemicals.(Gardener, et. al. 2008, 5
) Maternal birth abroad is thought to be associated with autism spectrum disorders because a woman born in another country may not be immune to common infections of the country she gives birth in, and as a result, she may contract an infection that increases her child's risk for autism. (Gardener, et. al. 2008, 15
) Diabetes and uterine bleeding during pregenancy is thought to have lasting autistic consequences of offspring because it causes a large hormonal imbalances and deprives oxygen in fetuses. (Gardener, et. al. 2008, 17, 20
) Last, exposure to toxic chemicals increases the risk of autism spectrum disorders either because the chemicals' toxicity directly injures the brain or the chemicals' makeup negatively alters genetic sequencing. (Landrigan 2012, 11
) All environmental exposures have the largest possibility to affect autism during unique "windows of vulnerability" that only occur during certain stages of embryonic and fetal life. (Landrigan 2012, 7
) After learning about the genetic and environmental causes of autism, one can concoct what they believe is the ultimate cause of autism spectrum disorders.
Altogether, autism spectrum disorders are disorders which have unique background information, a wide spectrum of symptoms, and genetic and environmental influences. Regardless of the common belief that these disorders can be caused by vaccinations, scientific studies have proven otherwise. Because this belief has proven to be false, scientists have moved on to studying actual environmental and genetic factors of autism. From this evidence, one can decide for themselves if autism spectrum disorders are caused primarily by genetics, primarily by the environment, or a combination of both.
By using scientific and anonymous resource information, I personally feel that autism spectrum disorders are caused by a combination of environmental and genetic factors. Some cases, I believe, are caused primarily by copy number variants, a genetic influence. After examining researches
, I feel that cases would only be entirely genetic if an old paternal age was involved or parents both had recently shared ancestry. I also feel cases would only be entirely environmental if the fetus who later develops an autism spectrum disorder was deprived of oxygen in some form or was exposed to a toxic substance . For the remaining cases, I feel environmental factors, such as the chemical make up of a substance, interact with the genetic make up of an individual and cause the genes to become mutated. I believe these mutated genes then incorrectly code for essential proteins, leading one to suffer from symptoms of autism spectrum disorders.
(PS: this was really good..)