The genetics of autism and schitzophrenia

Wow, 1.142857143 week & two posts - something must be wrong with me.

Anyone who knows anything, knows that autism is largely - if not entierly - a genetic "disorder". Disorder is in quotes since I think its arguable that some forms of autism represent normal neurovariation, rather than a disease/disorder.

Anyhoo, its also been long known that schizophrenia is also a genetic disorder, and as we've delved into the genetics of both diseases we've found some startling things - notably that many of the genes linked to one disease are also linked to another.

In the early edition of PNAS today (or at least I noticed it today) is a paper that looks at these linkages closely, and finds something very interesting. But before we go into that, lets set the stage:

One of the more common, but least understood, forms of human genetic variation is copy number variations. This simply means that some people will have more copies of a particular gene that others, and some will have less. This can result in biological abnormalities, as some genes need to be present in the right "dose" - too little or too much equals trouble. Many of the genetic variations found in autistics and schizophrenics are these kinds of variations - extra copies, or missing copies of genes.

In this particular paper, Crespi, Stead & Elliot show that autism is schizophrenia's genetic opposite - in cases where schizophrenics have gene duplications, autistics have gene deletions. And the opposite is also true - where autistics have duplications, schizophrenics have deletions.

This is a very interesting finding, as it tells us a lot about what is going in these disoriders. Notably, autism seems to occur when genetic mutations remove the breaks of developmental pathways - autistics seem to have unregulated brain development. Schitzophrenics seem to be the opposite - rather than having out-of-control brain development pathways, they instead have broken brain development pathways.

Of course, the anti-vax loons will ignore this study, and all that in means, inorder to preserve their faith in the non-truth that vaccines cause autism.