http://news.yahoo.com/fraternal-twins-autism-risk-womb-200138403.html;Most of the risk of autism has been blamed by experts on inherited genes. Now one of the largest studies of twins and autism shifts the focus to the womb, suggesting that the mother's age and health may play a larger role than thought.
The new research doesn't solve the mystery of what causes autism. Most scientists think faulty genes and outside factors are both at work. And since autism spectrum disorders include a wide range of conditions, from mild to severe, it's unlikely there's a single cause for all of them.
I think it's provable that there are different causes of autism, because for one thing they produce different symptoms, and different degrees of symptoms. The definitive symptom is probably reduced mirror functioning, but there's probably also something going on with summarization and filtering of data.
I'm not convinced that the genes are necessarily "faulty". At least in some cases, unlikely to produce the undesireable symptoms unless the environmental trigger activates. Autism is strongly associated with traits that are not themselves credibly "faulty"--for example, masculinity or a knack for math and engineering.
By the same token, really good actresses are more vulnerable to borderline personality disorder (the late Elizabeth Taylor had this, it can now be revealed--and dozens of other actresses have it too but I won't mention names) and histrionic personality disorder (the late Natalie Wood). Ironically almost certainly related to TOO MUCH mirror activity--almost the opposite of autism. The very trait that makes them good at acting (lots of mirror activity) also makes them vulnerable to runaway mirror activity (their emotions start feedback looping on themselves...).
"We've identified lots of vulnerability genes, but not everybody who has them gets autism," Goldstein said.
That's because they're not really "faulty"--simply more vulnerable to autism--but not to other problems. Pick your poison.
The new study found, as expected, high rates of shared autism disorders for identical twins: 77 percent of male twin pairs and 50 percent for female pairs had autism in both twins.
Surprisingly, it also found fairly high rates of fraternal twins both having autism spectrum disorders: 31 percent rate for male fraternal twins and 36 percent for female fraternal twins.
Other studies have found 10 to 20 percent of younger siblings of children with autism are likely to be diagnosed themselves with the disorder.
One possible effect of sharing a womb might be hormonal levels. Note the correlations are not perfect; it's not just genes.
In another study published Monday in the same journal, researchers found a higher risk of autism among children born to mothers who took antidepressants during the year before birth, particularly in the first three months of pregnancy.
It's too early to advise pregnant women against antidepressants, however. Untreated depression also can be harmful to mother and baby, said lead author Lisa Croen of the Autism Research Program at Kaiser Permanente, a large health maintenance organization in California.
Despite the link--and also a possible link to increased risk of suicide, which is somewhat admitted in the case of young patients (you have to wonder how effective they are if they sometimes backfire)--they apparently aren't even going to so much as WARN women about the possible links.
