Tuesday, July 24, 2007

A Unified Theory of Autism?

The Autism Knowledge Revolution is picking up pace and seems at times to be adding to our knowledge of autism on a daily basis. A new study offers a genetic mutation model of autism acquisition which the scientists involved suggest may help unify some of the current disparate theories of autism. The theory involves mothers acquiring and passing on autism related genetic mutations to their children. The mutations are spontaneous, arising from assaults to chromosomes. The assaults can arise from a wide range of unspecified environmental facts including naturally occurring cosmic rays and environmental toxins and contaminants. In addition to maternal transmission of the autism related genetic mutation older moms are indicated as being more likely to have an autistic child according to this study by geneticists at Cold Spring Harbor Laboratory. Scientists from the Kennedy Krieger Institute and the Albert Einstein College of Medicine in the Bronx collaborated in the study. The data network developed by iancommunity.org also assisted the reasearchers in the study. This purported Unified Theory of Autism seems to fit with the autism research paradigm shift mentioned in an earlier post. Environment versus genetics as competing and conflicting theories of autism causation seems to be giving way to environment and genetics as a unified theory of autism develops.

From Newsday.com:


A new model for understanding how autism is acquired and passed from one generation to the next is being offered as a grand unification theory that links other theories and illustrates how women play a key role in transmitting the disorder, scientists reported yesterday.

Geneticists at Cold Spring Harbor Laboratory have been on a genome-wide hunt to pinpoint the genes that cause autism, a brain disorder that usually appears within the first three years of life and can result in difficulties in learning, language and social interaction.

As part of their search, geneticists at the laboratory have collaborated with scientists at Albert Einstein College of Medicine in the Bronx and crafted a working theory of the disorder to aid not only scientists, but also physicians and families coping with autistic children.

"We're really unifying a field that people didn't realize needed unification," said Cold Spring Harbor molecular geneticist Michael Wigler, who, along with his colleagues report results of their research in the Proceedings of the National Academy of Sciences.

What Wigler and his team found is a previously unrecognized pattern: Mothers, they say, acquire genetic mutations spontaneously that are specific to autism, which can be passed to their children. The mothers do not themselves exhibit traits of the disorder, but they have a 50 percent chance of transmitting the trait.

Wigler describes spontaneous mutations as significant assaults to chromosomes that alter the function of genes. In addition to mothers playing a key role transmitting the autism-related mutations, Wigler said older mothers are more likely than younger ones to have an autistic child.

Genes can be damaged, he said, by cosmic rays that occur naturally, toxins and a vast array of environmental contaminants that have yet to be identified.

"There's very definitely a male/female disparity in autism," Wigler said, but there is still isn't strong evidence explaining why boys are more affected than girls. Boys are three times more likely than girls to develop the condition, Wigler said.

Paul Law of the Kennedy Krieger Institute in Baltimore, a collaborator on the project and the father of an autistic son, said hunting down genetic clues to autism will offer clarity in the face of a mystifying condition.

He and his wife, Kiely, developed iancommunity.org, a database that not only helps families but also aided Wigler in the study reported today. The database includes information on autism from families throughout the United States.
"This demonstrates the power of the families, that they are a valuable source of information and that's really the building block," Law said.


Anonymous said...

I am one of the leading author of this research. The report on Newsday is not very clear. The story on Scientific American website is better.

I would like to clarify our theory a little bit.

We hypothesize that asymptomatic mothers (and sometimes fathers) who acquire the spontaneous mutations from their parents are the main source of high risk families, whose sons have 50% chance of getting the mutation and be autistic, and daughters have the same 50% chance of getting the mutation but most show no (or very little) symptoms even with the mutation. Their children again will have high risk.

One the other hand, most of the autistic children have the spontaneous mutation not carried by their parents. They are from what we called low risk families. The mutation happens in the sperms and eggs of the parents, This risk is in general low but gets higher for older parents. Their siblings do not have the same high risk as those in the high risk families. There is no implication that spontaneous mutation are more likely from the mother than the fathers. We suggest that 2/3 of the girls who obtained such mutations are asympotomatic, and become the source of high risk family once they start having children.

Unknown said...

kenny ye

Thank you for clarifying your theory. It is a privilege to have your comment and insights on this blog site.

I am really amazed at the rate at which our understanding of autism is increasing today and the incredible research which is providing that understanding.