Is autism caused by genes or the environment? It’s a misleading question. As with so many complex behavioral conditions, the answer almost certainly involves a combination of both.
It’s frustrating, then, to see the results of the largest-ever autism genetics study greeted with headlines like this: “According to The Autism Genome Project, Chromosomal Abnormalities -- More Than Environmental Toxins -- Are Cause of Condition.”
In the study, scientists used new DNA sequencing technologies to compare the genomes of nearly 1200 families with autistic children. They found mutations concentrated in a chromosome region not previously implicated in autism, discovered an unexpected role for subtle genetic differences called Copy Number Variations and became very excited about a group of genes that code for neuron communication.
It’s very promising research. But there isn’t enough there to suggest that science has suddenly “tamed the immense complexity” of the genome, or that “environmental toxins are not, as some argue, a major cause of autism.”
The latter point is particularly contentious, given the uproar over whether a mercury-containing vaccine ingredient causes autism. (Apparently not.) But there’s much more to environment than vaccines –- and unless people carrying autism-related genes have developed in recent decades the power to unerringly find each other and breed, it’s hard to square the continuing spike in autism rates with the steady rates expected of a genetic disorder.
The Autism Genome Project has done a tremendous job of identifying genes that appear to be somehow involved in autism. What those genes do -- how they interact with each other, how their expression is influenced by diet or stress or chemicals, how individually and together they affect a child's development -- is not understood.
Until we have a bit more than that, any report that says autism has a simple genetic –- or environmental –- cause should be taken with a few grains of salt.
Study Suggests Autism Causes Are Genetic [ABC News]
