The team found a total of six mutations affecting genes that had previously not been linked to autism. The mutations came in the form of deletions, where part or all of both copies of the genes were missing in a child with the disorder. All of the genes are known to be involved in parts of the same process: creating and strengthening synapses.

Normally, when nerve cells (neurons) activate in response to an environmental factor (such as processing a new face or a new sound), synapses between two active cells change to provide stronger connections so the cells can pass on information more efficiently. As the brain develops, new connections are continuously formed among nerve cells, reinforced and, in some instances, broken as the brain starts to mature and divvy up its different functions to specific groups of neurons.

According to the findings, “All of the relevant mutations could disrupt the formation of vital neural connections during a critical period when experience is shaping the brain,” says Thomas Insel, director of the National Institute for Mental Health (NIMH) in Bethesda, Md. To wit, most children are diagnosed with autism between the ages of one and three years of age.

Walsh says the team believes these deletions—which in most cases found here only remove some, but not all, of the DNA that makes up a gene—may mean that the genes can regain some of their normal function. In fact, some of these genes may just be switched off. “This presents the possibility that in some kids we could get the gene going again without necessarily having to put it back in the brain,” he says.

Jim Sutcliffe, a molecular physiologist at Vanderbilt University in Nashville, Tenn., in a Science editorial notes that the majority of autism research is geared toward prenatal development, even though the brain continues to develop well after a child is born. “Experience and environmental input play an important role in subsequent development,” he says. He calls the notion that learning in early life is disrupted by these autism genes “an intriguing proposal,” but says that further research is needed to validate it.

Dan Geschwind, a neurologist at the University of California, Los Angeles, says that to test the hypothesis that autism genes affect synaptic strength, it would be important to examine the 20 to 30 other genes that have been implicated in autism and see which ones also play a role in strengthening neuronal connections. “If its a significant proportion,” he says, “that would provide support for the hypothesis being put forward.”

I was kind of trying to say this in my comment above—–Charlie got the kind of early intervention that the researchers refer to and it laid a solid foundation for the learning he has continued to do (and still continues too—-and still needs). The notion of genes that need to be “switched on,” by whatever way (a drug; behavioral therapy) seems to underscore the need, again, for education at any early stage.

David Brown, Washington Post
“…Marriage between first cousins doubles the risk of neurological birth defects. The researchers said they think that shared ancestry would increase the risk of autism caused by recessive mutations that cause problems only when a child inherits the defective gene from both parents. By studying cases caused by such rare events, researchers can often learn about the biochemical and genetic underpinnings of the far more common cases in which there is no inbreeding. ”
…
As RAJ noted about what else might be going on/phenotype

“…The researchers looked for one of the gene defects in autistic children whose parents were not related and found it, but it remains unclear how applicable this study is to garden-variety autism.”

(too bad the reporter could not be more specific about what is “garden-variety autism”; kind of curious about what is meant there.)

Many of the Middle Eastern children had other neurological problems, such as epilepsy. Whether the activity-driven gene defects are also present when autism occurs by itself is unknown. “

Given that there is probably not ONE autism, it doesn’t make me too crazy that multiple sources are being investigated, and I understand why they might pick a particular cohort to amplify the regions that they wish to study.

The point about the phenotype is taken. My understanding is that there was some work preliminary to this study–what was the phenotype there?

“Just over 6 percent of the 88 families showed rare, inherited deletions within DNA regions linked to autism”

Here again a handful of cases beinbg presented as ‘new autism genes discovered’. Inbreeding has long been known to cause mental retardation. This study does not report on the phenotype being discusssed. Is it ‘autism’ or mental retardation with some ‘autistic-type’ features.

Some of the children that we are bowling with attend an out-of-district but public autism school that we could have easily and automatically have gotten Charlie into, without moving, or a lawyer, or anything. Everyone seems to be doing fine but—at the risk of offending someone about what’s “quality” and what’s not—-there are some things about the program that Charlie is in that make it really “quality.” Sorry to be elusive; I don’t like judging or comparing anyone, but I knew there was a reason I did not want Charlie to be in that particular program.

I was really interested in the mention of education in relation to this study (and the Time article refers to autism as a “mental disorder”).