Autism may not just be a matter of genetics. A new international study suggests that the gut microbiome – the community of bacteria that live in our bodies – may play a key role in the development of autism spectrum disorders.
This is according to Italian scientist Alessio Fasano, professor of pediatrics at Harvard Medical School and director of the international GEMMA project, a study funded by the European Horizon 2020 program, which includes universities and research centers from Europe and the US.
"We are building the foundations of a building. It will take time to finish it, but without foundations everything would be impossible," Fasano said during the presentation of preliminary results in Salerno.
According to him, the drastic increase in autism cases in recent decades cannot be explained by genetics alone. "Forty years ago we had one child with autism in 10,000 births. Today we have one in 41 in the European Union and one in 36 in the US," he said.
The GEMMA study analyzed over 21,000 biological samples from children at high risk for autism, especially those who had siblings with this diagnosis.
According to preliminary results, scientists have identified a "critical window" between the ages of 3 and 12 months, where changes begin to appear in the gut microbiome of children who later develop autism.
Fasano explains that these children experience a decrease in protective bacteria, such as bifidobacteria found in breast milk, and an increase in harmful bacteria such as Clostridia. At the same time, there is an increase in zonulin, a protein that regulates intestinal permeability and can activate the immune system and inflammation.
The study also suggests that cesarean section birth and artificial feeding may be associated with a higher risk of autism compared to vaginal birth and breastfeeding, precisely because of their impact on the microbiome.
However, Fasano warns that this is not about "curing autism."
"Please, don't make headlines about discovering a cure for autism. After this, there are families with high hopes and no illusions should be created," he said.
According to the researcher, the results are promising, however. In some cases, the use of probiotics and prebiotics has led to improvements in gastrointestinal and behavioral symptoms in children with autism.
The objective of the project is that in the future, autism diagnosis will not be based solely on behavior, but also on biological biomarkers that can help in the early identification of children at risk and in more personalized interventions.
