International study identifies genes associated with autism

From the LA Times:

A large international consortium of authors (including some at UCLA) have identified new genes that appear to be involved in autism somehow. The findings appear in the journal Nature.

The researchers in this big effort examined the DNA of 996 children with autism spectrum disorder plus their parents, and compared what they found with the DNA of 1,287 matched controls (who didn't have autism but were of similar ancestry, etc). They looked for differences between the two groups in places in the genome where chunks of DNA are repeated or deleted.

Such repeats or deletions were found 20% more often in the autism group -- some of them situated at genes that, therefore, may be involved in the condition. The implicated genes appear to be involved in functions such as nerve connections and nerve growth, and others had been implicated in learning disabilities.

In some cases, the parents also had these little duplications or deletions, implying inheritance. In other cases, the kids had them but the parents did not, implying, perhaps, that they had developed in sperm or eggs that gave rise to the children.

That genes are involved in autism is not a surprise: The condition is known to run in families, and twin studies indicate inheritance. And previous studies have identified some genes. But this was the biggest autism-DNA study yet, and it adds to the list of genes that could be involved in autism.

The study doesn't produce any kind of diagnostic test, since the genes identified don't definitively predict autism, but just indicate heightened risk (some of the researchers are now working on a project to see whether the genes can help in diagnosis of new cases of autism). And they also don't explain more than a fraction of autism cases.