You may have heard about a new UC Davis study showing that parents of a child with autism are substantially more likely to have another child with autism. While it’s already been established that an infant who has an older sibling with autism has a greater chance of developing the disorder, this new research ups the odds to about 19 percent, from the previous estimate of 3 to 10 percent. A release about the findings, which are to appear in the September issue of the journal Pediatrics, was posted online yesterday.
This research is the latest twist in the effort to untangle what is behind autism, a neurological disorder estimated to affect one of every 110 children born this year. Although some of the past culprits — vaccines and uncaring mothers — have been ruled out as causes, there remains much confusion about how much the disorder results from environmental factors, genetics or increased awareness and diagnoses of the disorders. Last month, for instance, a Stanford release about a new paper reported that “non-genetic factors play an unexpectedly large role in determining autism risk, turning upside down recent assumptions about the cause of this common, disabling developmental disorder.” Now we have this new study saying genetics matter more than you might think.
This sort of back and forth is, of course, the way that science advances, but that doesn’t necessarily help clarify things for parents of a child with autism deciding whether or not to have another baby. A post on a New York Times blog tries to put it in perspective:
The findings prompted child development researchers to urge greater awareness for families who have a child with autism and may be considering more children. Although 1 in 5 is a greater risk than previously expected, it still means that 4 out of 5 children with an autism spectrum disorder will not develop the condition, said Alycia Halladay, the director of environmental research for Autism Speaks, an autism research group that supported the study along with the National Institutes of Health.
“Family history is a very strong risk factor, but there are other risk factors as well,” she said. “There are strong environmental risk factors. We don’t know what those are yet, but this is not the only factor that goes into an autism diagnosis.”