Photo by mknowles (Flickr)
According to The Scientist a recent study is casting doubt on the assumption that all tissues in your body contain exactly the same DNA. Researchers found that the genetic material found in blood may differ from that in other tissues in the body.
The researchers in question were searching for the genes responsible for a fatal condition and found "that complementary DNA from diseased abdominal aortic tissue did not match genomic DNA from leukocytes in blood from the same patient."
Needless to say this could cause problems for autism studies that rely exclusively on blood samples for genetic material, like say this one or this one or this one or any other study that relies heavily on data sets like the one provided by AGRE.
This doesn't mean that these studies are wrong per-se, it just means that they might not be looking at the complete picture. Maybe the problem with finding the genetic cause of autism is because we aren't looking in the right place?