Babies with siblings with autism are at high risk of developing the condition. They have a roughly 1 in 5 chance, compared with about 1 in 100 in the general population. Two studies published in 2017 report that brain scans predicted which infants with siblings with autism were most likely to develop autism themselves. The first study showed that infant siblings who have the fastest brain growth in their first year of life have the highest risk. The second study showed that brain functional connectivity — how regions in the brain work together — at 6 months of age accurately predicted which infants would have an autism diagnosis at age 2.
The research, published in Science Translational Medicine in June 2017 and in Nature in February 2017, might one day help doctors identify autism much earlier than is currently possible. Most behavioral symptoms of autism aren’t easily detectable until a child is at least 2 years old, and it is generally not possible to diagnose children with autism until at least that age. The new studies show that differences in brain growth and function in babies who will develop autism are evident as early as the first year of life.
Researchers used a machine-learning algorithm to predict which infants would develop the condition. In the June study, they correctly identified 9 of the 11 babies who would develop autism by age 2, from a total of 59 in the study.
These findings have caught the attention of both scientists and the media. Many press reports focused on the new possibility of diagnosis before age 2. However, much more work is needed before a useful screening test will be available. These studies need to be replicated in larger numbers of infants. A practical barrier is that brain scans are too costly to use as a broad screening tool. Nevertheless, researchers hope that they can build on these results. They aim to find brain features that predict autism and can be detected using cheaper technologies, such as electroencephalography, or EEG.
These two studies highlight the importance of long-term research in autism. Joseph Piven, a neuroscientist at the University of North Carolina, Chapel Hill, and a SPARK investigator, launched the study 10 years ago. He notes that finding participants was the most challenging part of the project. The project — known as the Infant Brain Imaging Study — has come to a close, but the researchers aim to extend their efforts. More information about future research can be found here.
For additional details, check out these two pieces from Spectrum, an editorially independent news site funded by the Simons Foundation.