Largest Autism Study Further Highlights Genetic Link
> 2/20/2007 1:12:04 PM

In the largest single recorded study dealing with autism spectrum disorders, researchers worldwide combined information gathered from more than 1200 affected families as part of a five-year endeavor, known as the Autism Genome Project, which was sponsored by the non-profit group Autism Speaks and the US National Institutes of Health. While their conclusions do not, of course, conclusively name a single cause or definitive medical response to the epidemic, they've accumulated a staggering amount of evidence pointing directly toward a genetic basis for the condition.

The variables in this study were more specific than those of past efforts as well: researchers only observed families with at least two autistic members, using this subject base to verify certain previously held beliefs such as the fact that if one identical twin is autistic, there is a 90 percent chance that the other shares the same disorder. That statistic alone hints at a prominent genetic predisposition, but researchers also highlighted two neurological components which most likely play a crucial role in determining one's proclivity toward autism: the 11th chromosome and a brain-shaping protein known as neurexin 1. The broader theory holds that irregularities in the pre-natal development of the nervous system lead directly to the condition. Other observations of note were the common presence of genes appearing in unusal form and number, or "copy number variants". While genes generally come in pairs influenced by both parents, many of these genes appeared as independent elements in sets of three or more. These arrangements were not present in parental DNA, leading one to belive that the issue, again, arises some form of developmental irregularity, and most of the problem genes occurred in the 11th chromosome.

The major potential application of the study, according to its authors, is developing genetic tests for early diagnosis and basing new forms of treatment around their results. As with most developmental conditions, early awareness is crucial in respect to autistic individuals. Without this knowledge, they may be forced into inhospitable environments armed only with the hope that they will develop into "normal" children. Late diagnosis may arrive only after years of frustrating speculation and unsuccessful interventions. Still, these findings do not dispel the commonly held belief that one's environment plays a major role in determining a diagnosis of autism. In the words of one of the study's lead authors:

"Remember, autism is actually a grab bag of different developmental disorders. And what we show here is that many genes can be involved, and also these copy number variants. And could it be that environment is contributing? Absolutely."

Like any project of this magnitude and significance, its results must be very carefully studied before any grand proclamations are made. Its greatest contribution to the autism debate may be in validating further, more detailed and wider-reaching research using the same model and focusing on the same variables. As families dealing with autism already know, patience is a learned and indispendable element of the equation.

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