The New England Journal of Medicine published a study yesterday showing that small changes in the DNA in the long arm of chromosome 16 are associated with autism.
I met a teenager with autism last summer, when I attended family night at the Seattle Park and Rec summer camp program for kids with special needs. It's a fantastic program. The kids spend a week or more at summer camp and the parents get some much needed time off.
I sat down on a log and my daughter (one of the counselors) introduced to me a boy in her cabin and told me that he's interested in trains. Since I rode a train for three days once when Northwest Airlines went on strike, I told him about it. For the rest of the night we talked about trains. Every few minutes, he would look at me and tell me something about trains and where they run.
"Sandy, did you know that there's a train station in Seattle?"
Yes, I do.
"They go to California and north all the way to East Coast."
hmmm, uh. cool.
15 minutes later.
"Sandy, did you know there are trains that run through Seattle?"
This went on all night until I left.
When you meet people with autism, it's hard not to be interested in what makes them the way they are. We do know that many cases are inherited and that 10% of the cases have been linked to specific abnormalities in chromosome structure, but the cause (or causes) of the other 90% of the cases has remained a mystery.
The study by Weiss, et. al. looked at all 46 chromosomes in 751 families in search of genes related to autism.
They found that 1% of the children with autism from these families had changes in the DNA in the p11.2 region of chromosome 16. The changes were either duplications or deletions of a 147,000 base region of DNA. The children with autism had changes in this region, their parents (without autism) did not.
It's not yet known which of the 25 genes in this 147,000 base region is related to the development of autism, but the trail is getting warmer.