In the continued saga of Steve Silberman strangeness, I just happened to be reading a piece written a few months ago by this person who is now the most prominent popular writer on autism related matters. The piece has (at least to me) the offensive title Autism is a valuable part of humanity's genetic legacy. The phrase that stands out most prominently to me in the article is this:
In recent years, researchers have
determined that most cases of autism are not rooted in rare de novo
mutations but in very old genes that are shared widely in the general
population while being concentrated more in certain families than
Since Silberman neglected to cite any source for this, I'm curious where he got this information since it completely contradicts everything that I've read about autism genetic research that's taken place in the last eight years or so.
Jonathan Sebat for instance has published research showing a significant association between autism and de novo mutations. Dr. Sebat states that he expects that the actual cases of de novo mutations is in reality substantially higher than what he found since the techniques for identifying these genetic abnormalities are still not advanced enough to find spontaneous mutations on the genome that might be even smaller than those already identified.
A study done in Israel several years ago showed that children of fathers over the age of forty were nearly six times as likely to have an autism spectrum disorder than the offspring of younger fathers. It was considered probable that this was the result of de novo mutations in the sperm of the older dads.
A very recent study done at Cold Harbor Springs lab has suggested that probably half of all cases of autism are caused by rare de novo mutations on genes that have a particular vulnerability and that these are not old genes as Silberman claims, but are expunged rapidly from the population since autistic people rarely have children. Previous research done by this group showed that some of these de novo mutations were carried by the mothers who had a protective effect against autism but their children (usually boys) inherited them in an autosomal dominant fashion.
This is just a small sampling of articles that suggest rare de novo mutations not found in the general population are a significant factor in autism spectrum disorders.
The Slate article was apparently excerpted from the Neurotribes book. It's been a while since I've read neurotribes and I can't recall if Silberman wrote this in the book or if he gave any references to any actual genetic studies that support his statement. Since there's been so much science that contradicts what he says, I'm wondering if this research exists, could Silberman or anyone else cite any references since I can't seem to find any on the internet. Maybe there's something out there, but it would seem that Silberman has made statements on the genetics of autism that have no factual basis as was the case with his statements on Kanner's work. Even if there were such research, Silberman would have to explain why he said what he said in light of recent research that has found that a significant number of autism cases are the result of de novo mutations.