Autism Genetics and Gender

I have to think back to when Charlie was in preschool to when there was a girl in his autism classroom. It's commonly stated that boys are four times more likely than girls to be on the autism spectrum, though there is some dispute about whether or not autism is underdiagnosed in girls, and if autism presents differently in women. The May 19th Time magazine reports on a Molecular Psychiatry study which describes CACNA1G, said to be an "autism-risk gene." CACNA1G is more common in boys than in girls:

CACNA1G, which sits on chromosome 17, amid other genes that have been previously linked to autism, is responsible for regulating the flow of calcium into and out of cells. Nerve cells in the brain rely on calcium to become activated, and research suggests that imbalances in the mineral can result in the overstimulation of neural connections and create developmental problems, such as autism and even epilepsy, which is also a common feature of autism. .................

"Overstimulation of neural connections"---that sounds familiar as far as extremes of experience, and also synapses and neuronal connections. Time magazine continues:

For the new study, researchers at the University of California, Los Angeles (UCLA), combed the genetic database of the Autism Genetic Resource Exchange (AGRE), a resource of DNA from 2,000 families with at least one autistic child. The scientists focused on the more than 1,000 genetic samples of families in which at least one son was affected by the disorder, prompted by the results of an earlier study using the same database, which identified a rich autism-related genetic region on chromosome 17 that contained genetic variants more common in boys than in girls. While nearly 40% of the general population has the most common form of CACNA1G, one variant of the gene was more prevalent in autistic boys, researchers found. "There is a strong genetic signal in this region," says Dr. Daniel Geschwind, director of UCLA's Center for Autism Research and Treatment and one of the study's co-authors. "But this gene doesn't explain all of that signal or even half of it. What that means is that there are many more genes in this region contributing to autism."

Chromosome 17 has been previously noted as the site of an autism gene. With scientists identifying more genes that can be linked to autism, it's no surprise that there's been quite a bit of discussion about a prenatal test for autism and the ethical implications of this. Some years ago, a hospital in London was hoping to develop a test to screen for autism in male embryos for couples with a family history of autism; the fact that autism occurs more frequently in males than in females was noted.

All of these findings from research suggest that some kind of test could be developed before we know it and I'm for having a regular, thoughtful public discussion about these topics. They're about a huge issues that we're only beginning to articulate the implications of.