It’s been a big month for autism news. With the release of widely publicized results during this year’s Autism Awareness Month, we have yet more clues as to the disorder’s genetic and environmental makeup. In fact, to read the headlines, you’d think we’re on the cusp of a game-changing breakthrough.
It’s true that the science is gaining momentum. But the story of autism seems to get more complex with every discovery, making the roots – and more importantly, the treatments – look ever more elusive.
The major buzz this month is around a series of papers in the journal Nature that point to some of autism’s underlying DNA mutations. In three studies, researchers analyzed blood samples from people with and without an autism diagnosis and singled out genetic changes that may increase the chances of a person developing autism. This follows another large-scale set of studies, the results of which were released in 2010. Here, scientists looked at genetic hiccups called “copy number variants,” and estimated that people with the diagnosis are 20 percent more likely to have these glitches in their DNA – many located in genes that code for brain development. Genetic research is starting to boom with discoveries, and the advances are important because they put up signposts in a massive, wide open landscape and give scientists clues about where to look next.
But the breakneck pace within the world of science is still incremental to the outside world. To put it in perspective, each of these findings is the result of years of work by teams of scientists, but still represent a fraction of the genetic picture of the disorder (some estimate around 3 percent of cases could be explained here). In combination, the work has put a finger on a collection of suspect genes, but most experts believe that roughly 1,000 genes could be involved in the development of autism.
To make things more complicated, each person with autism probably has a different genetic profile or combination of DNA mutations. We know that autism isn’t one disorder or even one spectrum – it’s a collection of varied disorders. So scientists aren’t actually hunting for one cause, they’re putting together pieces of many different puzzles all at once.
And the final twist: There is no way to separate nature from nurture. The environment doesn’t swoop in and cause autism (as with the debunked vaccine myth), just like genes don’t program directly for the disorder (identical twins don’t always both have it). Dozens of variables have been shown to increase the risk of autism: father’s age, low Apgar score, low birth weight, closely-spaced births, summer births, and most recently, maternal obesity. What this probably means is that if a baby has one or two of the hundreds of possible DNA mutations, the environment could turn on or silence them in a way that guides the brain towards characteristics of an autism spectrum disorder.
Again, the science is fascinating – I’d love to see the same fervor around treatments that help affected children and families. In the next few years we’ll be hearing a lot about the unfolding genetic story and how nature and nurture work together. For now, though, it seems that the more we know, the more we realize we don’t know.