Autism: Any Closer to a Cause?
By: Beth McHugh 2010
Autism is known as a pervasive developmental disorder. The term pervasive suggests that the effects of the disorder will significantly affect the individual throughout the course of their lifetime.
Autistic disorder is characterized by significant impairment in social interactions and communication and by a restricted pattern of behaviors, interests and activities. Autism varies in intensity between individuals such that, in the best case scenario, individual programs during early intervention schemes should be designed for each child’s abilities and strengths.
We have previously discussed the diagnostic specifications for a diagnosis of autism (see links below) but what is less known among researchers is the cause of the disorder. Statistics from Australia suggest that in the early 1960s the number of Australian children diagnosed with autistic disorder was around one in 20,000. Today, the figure is closer to one in 160.
This represents an enormous increase in the occurrence of the disorder. Reason suggests however, that autistic disorder has in the last decade had much more attention in the media. Like ADHD in the 80s, autistic spectrum disorder is much more in the public eye. As with many children who were diagnosed with ADD and ADHD back then, and given unnecessary drug treatment as they did not have the disorder at all, many are now being assessed as having an autistic spectrum disorder when in fact they have another problem entirely.
Nevertheless, the condition does seem to be on the increase and scientists are looking at possible reasons why. With the advent of genetic testing which was not available during most of the last century, we can at last look at some of the causes for this puzzling disorder.
The scientific journal Nature reports that a group comprising of hundreds of researchers have discovered dozens of previously unknown genetic mutations than can give rise to the behaviors that form the pattern that is known as autism. This suggests that autism is caused not by a single factor but by many.
Some of the rare changes in the DNA of autistic individuals were found to be inherited from one or both of the parents so there exists a definite genetic link in the development of the disorder.
Professor Daniel Geschwind of the University of California states that “tiny genetic errors may occur during the formation of the parents’ eggs and sperm, and these are copied during creation of their child’s DNA”. Over 100o children from the US, Canada and Europe participated in this study which gives us a snapshot of the disorder on a worldwide basis plus gives a further indication of the strong genetic basis for the disorder.
There were also incidences of spontaneous appearances of autism in
children with no family history of the disorder. Clearly, there is no
one cause for the disorder, rather it is a complex condition where both
genetics and in utero conditions play significant roles.