Autism is a pervasive neurodevelopmental variant that occurs in approximately 2% of the human population. Compared to neurotypical individuals, autistic individuals tend to have a sensory experience that is more intense and unfiltered. Due to differences in social behavior and body language, autism is almost always a disability.
Common signs of autism
Common signs of autism are usually displayed before the age of 3 and last throughout the life of the individual. Below is a list of those attributes:
- situational or pervasive mutism, typically affecting oral speech only and not writing
- difficulty intuitively learning and recognizing the body language and other non-verbal communication of non-autistics
- preference for routine and sameness
- repetitive body movement (stimming) such as flapping one's hands as an expression of emotion or for self-regulation
- sensitivity to sensory input such as bright lights and loud sounds; may result in avoidance or seeking of said input
- preference for logic and literal use of language
Causes of Autism
Though the cause of autism has not been 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 autism. However, mutations such as single base changes have shown that autism can result from genetics, and also implicate that it can be hereditary. An autistic individual is six times more likely than a neurotypical individual 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. A correlation between paternally inherited DNA and paternal age shows that autistic boys were six times more likely than neurotypical boys to have a father in his 40s.
"Autism - Topic Overview." WebMD. Healthwise, 10 Apr. 2010. Web. 6 Dec. 2012. <http://www.webmd.com/brain/autism/autism-topic-overview>.
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>.