Autism is a disorder to the brain that makes it difficult for the individual to communicate and relate with others. The reason for this is because different areas of the brain are not able to work together.
Symptoms of autism are usually displayed before the age of 3 and last throughout the life of the individual. Below is a list of symptoms:
-difficulty with communication verbally thus giving the individual the inability to participate in a conversation
-difficult with non-verbal communication such as recognizing expressions and movements
-difficulty with social interactions thus giving the individual the inability to make friends
-lack of imagination
-difficulty adjusting to new things such as changes in routine or environment
-repetitive body movement such as flapping ones hand
-preoccupation with unusual objects
Though the cause of autism cannot be pinpointed to a specific source, two major sources have been identified as probable causes: genetics and environment.
In regards to genetics, studies have yet to prove that a gene is the single cause of this disease. However, mutations such as single base changes or have shown that autism can result from genetics and also implicate that it can be hereditary. An individual with autism is six times more likely to have a functional variant in genes expressed in the brain.
The environment also can affect the genetics resulting in de novo mutations, mutations that occur for the first time in a family member as a result of a mutation in either a sperm or egg cell. Research has shown that older men who decide to have children would most likely have a child with autism since sperm cells are at greater risks of mutations for older men. A correlation between paternally inherited DNA and paternal age shows that boys with autism were six times more likely to have a father in his 40s.
Insel, Thomas. "The New Genetics of Autism – Why Environment Matters." National Institute of Mental Health. N.p., 4 Apr. 2012. Web. 6 Dec. 2012. <http://www.nimh.nih.gov/about/director/2012/the-new-genetics-of-autism-why-environment-matters.shtml>.
"Autism - Topic Overview." WebMD. Healthwise, 10 Apr. 2010. Web. 6 Dec. 2012. <http://www.webmd.com/brain/autism/autism-topic-overview>.