A new study from the University of California San Diego School of Medicine presents a unified biological model that may explain how genetics and environmental exposures interact to cause autism spectrum disorder (ASD). Published December 9, 2025, in Mitochondrion, the research introduces a “three-hit” metabolic signaling model that reframes autism as a potentially treatable disorder of cellular communication and energy metabolism. The authors suggest that up to half of autism cases could be prevented or mitigated through prenatal and early-life interventions.
The model is built on more than a decade of systems biology research and proposes that ASD emerges only when three conditions align:
Genetic predisposition: Certain inherited genes heighten mitochondrial sensitivity and disrupt key cellular signaling pathways.
Early trigger: Environmental exposures—such as maternal or early infant infections, immune stress, or pollution—can activate a universal cellular stress mechanism known as the cell danger response (CDR).
Prolonged activation: When this stress response remains active for extended periods, typically from late pregnancy through the first two to three years of life, it disrupts normal brain development and helps drive ASD.
Central to this framework is the CDR, a short-term metabolic program that helps cells heal and adapt to threats. Under normal conditions, the CDR switches off once danger passes. But if it remains chronically activated—either due to persistent stressors or genetic hypersensitivity—it impairs mitochondrial function and disrupts cellular communication. This occurs through altered extracellular ATP–related purinergic signaling, which influences how neural circuits form in early life.
“Behavior has a chemical basis,” said lead author Robert Naviaux. “The CDR regulates that chemistry. When it remains activated too long, resources shift from growth to defense, leaving fewer resources for the developing brain.”
The model integrates decades of autism research, including findings on mitochondrial dysfunction, immune activity, gut microbiome changes, and sensory hypersensitivity. It also helps explain why genes and environment both contribute to ASD risk, and why neither alone fully accounts for the condition. Naviaux argues that this perspective shifts attention away from searching for a single “autism gene” and toward understanding how diverse stressors converge on shared biochemical pathways.
Because the second and third “hits” in the model are potentially reversible, early detection may significantly reduce autism risk. Naviaux compares the framework to phenylketonuria (PKU), a classical genetic disorder that can cause intellectual disability but is largely preventable when treated early. He estimates that identifying and supporting high-risk pregnancies and infants could prevent or improve 40%–50% of autism cases.
Potential early-screening strategies include maternal metabolomic profiling, autoantibody testing, and specialized newborn analyses to detect metabolic stress before symptoms appear.
The study arrives amid rising autism prevalence and continued debate over its causes. By framing ASD as a neurometabolic and neuroimmune condition, the authors hope to encourage collaboration across scientific fields and open new pathways for prevention and treatment.
Future priorities include refining diagnostic tools capable of detecting metabolic stress early and developing therapies that restore balanced energy and signaling systems. Naviaux calls for the creation of new antipurinergic drugs to regulate abnormal ATP signaling and urges large, multi-site clinical trials to test these treatments in children with ASD. He also advocates for prenatal and early-life screening programs that integrate genetic, metabolic, and environmental data.
These efforts aim to determine whether calming the cell danger response can prevent or reduce autism’s most disabling features.
“Understanding autism through the lens of metabolic signaling doesn’t just change how we think about the condition—it changes what we can do about it,” Naviaux said. “If we can recognize and calm the stress response early, we may be able to improve or even prevent some symptoms.”
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