Brain scans reveal two distinct types of autism

An international research team has discovered two biologically distinct subtypes of autism, each characterized by unique brain connectivity patterns. Led by the Istituto Italiano di Tecnologia (IIT) in Rovereto, Italy, and the Child Mind Institute in New York, the study analyzed fMRI brain scans from 940 children and young adults with autism, alongside data from 20 genetically engineered mouse models. The findings revealed one subtype with excessive communication between brain regions (hyperconnectivity) and another with reduced communication (hypoconnectivity), linked to synaptic and immune-related pathways, respectively. The study, published in *Nature Neuroscience*, was coordinated by Alessandro Gozzi, PhD, director of the Center for Neuroscience and Cognitive Systems at IIT, and Adriana Di Martino, MD, founding director of the Autism Center at the Child Mind Institute. The researchers combined human brain imaging with mouse model data to establish biological signatures, enabling them to identify distinct mechanistic pathways underlying autism. The team examined functional brain connectivity in the mouse models and compared it to human brain scans, also analyzing data from over 1,000 neurotypical individuals. The two identified subtypes accounted for about 25% of the autism cases studied, offering a foundation for future precision medicine approaches. The findings suggest that variations in autism may reflect underlying biological differences, potentially guiding more tailored treatments. Dr. Gozzi noted that the study provides the first large-scale evidence linking brain connectivity patterns to specific genetic and immune factors. Dr. Di Martino described the mouse models as a 'biological Rosetta Stone,' allowing researchers to decode how molecular mechanisms influence brain connectivity. The work highlights the importance of integrating genetic, imaging, and biochemical data to advance autism research and treatment strategies.