Genes ahoy!

It's been a while since my last blog post - in my defense She Who Must Be Obeyed is preggers, so my times been consumed prepping for the arrival of my son/daughter (by which I mean I've been freaking out - its scary, being responsible for someone other than yourself).

Despite that, a bit of science came out today that is worth spreading - we now have a detailed genetic map of autism - as in we've now identified most of the mutations which lead to autistic development of the brain.

I can hear the cries of dismay from the anti-vaxxers already. Let me pre-empt them - its all a conspiracy, aliens control the world, blah-blah-blah...

Now, for reality:

The paper I'm referring to was published this week in Nature: Functional impact of global rare copy number variation in autism spectrum disorders. Nature, Published online 09 June 2010.

What this group did was take DNA samples from 996 individuals with autism, and 1287 people without autism, and screened their DNA for small mutations - changes in the number of copies of genes (called copy number variants - CNV's). What they found was, in some ways, not to surprizing - they confirmed that many of the genes tenativly identified in previous screens are in fact involved in autism; in addition they identified a few more genes - SHANK2, SYNGAP1, DLGAP2 and DDX53–PTCHD1.

As before, the genes they identified play a role in mediating the communication between neurons. In a previous post I described many of the previously known genes involved in autism. These previously identified genes fall into one of two categories - genes that regulate the communication between one neuron and the next, and genes that allow neurons to target damaged proteins for degradation. These newly identified genes all appear to fall into the first category - , SYNGAP1 for example, regulates the cycling of neurotransmitters.
But what this paper did that was really exceptional was a gene-function map - meaning they grouped the genes they identified into groups based on their biological function, and then mapped the relationships between those groups:

(click on image for full-size)

What we see in this gene map is the identified mutations fall into several broad categories, notably:

1. Cell movement - required for proper brain formation, and is required for neurons to make connections between each other - both during embryonic development.
2. GTPase/Ras signaling - required for the controlled release and recycling of neurotransmitters
3. CNS development - genes involved in forming our brains during embryonic development
4. Adhesion - allows neurons to bind to each other
5. Kinase activity - a set of signaling molecules that allow neurons to receive signals from the outside environment (hormones, for example) and respond to them. Required for proper brain development during embryogenesis.

The above tells us a lot about what is going on in the formation and functioning of autistic brains. But there is something key in the above data - notably, points 1,3 and 5. The fact signaling pathways required for brain development in embryos is involved is proof-positive that autism is caused not by vaccines, toxins, or other products of "big pharma", but rather is a genetically-encoded disorder that forms while the child develops in the womb.

The other cool thing here is that we now have the possibility of detecting autism early - potentially before birth, or at a minimum, immediately after. we know the sooner you start with specialized training, the better autistics do in terms of their neurological development. By identifying these individuals on the day we are born, we will be able to intervene early - hopefully helping them overcome some of the deficits they face sooner, rather than later, in their lives.