Autism follow-up: first steps toward a genetic map

Here’s some real science about the cause of autism you can sink your teeth into (as opposed to the rumors and fear-mongering created by the misguided tin-foil hatters who promote the link between vaccines and autism…too harsh?). The Autism-Genome Project just published its second paper about the potential genetics behind autism.  Funded by internation, private, and public partners, the AGP is a consortium of over 50 research centers from Europe, Canada, and the US.  As family studies have demonstrated that autism-spectrum disorder appears to be an inherited trait (ie, one that is genetically passed down through families) the AGP aims to discover the specific genetic factors that cause autism.  The AGP just published an initial paper in the journal Nature titled Functional impact of global rare copy number variation in autism spectrum disorders. The study examined the genomes (the entirety of an organism’s hereditary information) of 996 individuals diagnosed with autism as well as a control group of 1,287 individuals who are not autistic.  They found that overall, autistic individuals were more likely to have a higher number of copy number variations within their genomes than the non-autistic individuals.  Copy number variations exist throughout the human genome, and are simply a stretch of the DNA that has been duplicated once or multiple times.  Some of these genetic variants pointed to genes previously implicated in autism or other related intellectual disabilities.  However, many of these genetic variants were found in networks of genes involved in more basic cellular functions, such as cellular proliferation (cell growth and division).

Interestingly, although autistic individuals did have a higher number of copy number variations than the control group, each of the copy number variations found were quite rare.  Unfortunately we can’t point a finger now at a specific gene, or even a specific gene family/network, as a single cause of autism.  This seems to make sense, as autism is really a spectrum of different disabilities with differing levels of severity.  If there is so much variability in the symptoms of autism, we could expect there would be an equal amount of variability in the underlying genetic basis for this disease.  So, while this new research is important from a genetics and scientific point-of-view, the potential applications of this information are off in the distant future.