The risk of developing autism-spectrum disorders is determined by the mother’s microbiome — the collection of microorganisms that naturally live inside us — during pregnancy, new research from the University of Virginia School of Medicine suggests. The work raises the possibility that preventing forms of autism could be as simple as an expectant mom modifying her diet or taking custom probiotics. Further, the UVA scientists were able to use their discovery to prevent the development of autism-like neurodevelopmental disorders in lab mice. They found they could halt the development of such disorders by blocking a particular inflammatory molecule produced by the immune system. Targeting this molecule, interleukin-17a, offers another potential avenue for preventing autism in people, the researchers say. They caution, however, that this approach would be much more complex because of the risk of side effects. “We determined that the microbiome is a key contributor in determining susceptibility [to autism-like disorders], so it suggests that you could target either the maternal microbiome or this inflammatory molecule, IL-17a,” said lead researcher John Lukens, PhD, of UVA’s Department of Neuroscience. “You could also use this [IL-17a] as a biomarker for early diagnosis.”