Wednesday, April 29, 2009

New Autism Studies Begin to Fill Out the Genetic Part of the Autism Equation

WebMD reports that three studies published online claim to have identified gene variants involved in about 15% of autism diagnoses. The research subjects were mostly children with autistic disorder diagnoses. Hakon Hakonarson, MD, PhD, director of genomics research at The Children's Hospital of Philadelphia and the lead author of two of three studies states that:

"the newly identified gene variants found to boost autism risk are involved in facilitating communication between brain cells -- making more credible the suggestions from other autism experts that autism or ASDs are due to abnormal connections between brain cells early in development."

Dr. Hakonarson also points out that having the genetic variant does not automatically mean that autism will result. Other genetic and environmental factors are also involved.

Dr. Thomas Insel of the NIH was interviewed by WebMD about the studies and also places the new genetic studies results in a genetic and environmental context:

"If you think about autism as a jigsaw puzzle with 500 pieces, each of these findings is an 'edge' piece. But many edge pieces are needed to make progress.

It would be a mistake for people to read this and think this is only about genetics. Almost everybody agrees that autism is a collection of different disorders. Some of them may be heavily genetic. But I think most experts would say the bulk of autism is the result of both genetic and environmental effects that are interacting in some way that we have yet to fully describe.

This begins to fill out the genetic part of the equation."

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Mercola said...

Sounds interesting. This is a great post especially to show support and care with those people who have relatives or loved ones having autism

RAJ said...

New Autism Gene Discovered!

Having failed to identify any autism specific genes, genetic researchers are now looking at common genetic variants. Common genetic variants are defined as genetic variants that occur in more than 5% of the general population.

The mass media reported with interviews from the authors that 65% of autistics possess this common genetic variation. What the mass media didn't state is that 60% of the general population also possess this same genetic variant on chromosome 5.

This represents a very small risk for autism (1.2) , as the authors state in the paper, but not when interviewed by the mass media.

To put the meaninglessness of the study in another context, there is a common genetic variance that increases the risk for autism by 4 to 9 times. This genetic variance is found in smaller rates in the general population (50%)than the common genetic variant reported in chromosome 5 (60%).

That genetic variance is the presence of of XY sex chromosomes which increases the risk for autism by a factor of 4 - 9 times.

The absence of this genetic variance, identified by XX sex chromomes instead of XY sex chromosomes significantly reduces the risk for autism in the general population.