A newly discovered biological chain reaction explains how high levels of a common brain chemical can lead to cellular overdrive in autism spectrum disorder. By tracing how nitric oxide disables a protective protein to accelerate cell growth pathways, researchers have identified a specific target that might one day yield new therapies. The findings were recently published in the journal Molecular Psychiatry. Autism spectrum disorder involves differences in brain development that affect social communication and routine behavior. The biology behind these changes involves many genes and environmental factors. Researchers have observed that a signaling pathway called mTOR often runs unusually fast in the brains of autistic individuals. The mTOR pathway acts as a central control center for cell growth, protein production, and energy use. When it functions properly, it helps brain cells build the connections needed for learning and memory. Yet the exact steps connecting autism risk factors to this hyperactive growth pathway have remained a mystery. A team of scientists suspected that nitric oxide might be a missing link. Nitric oxide is a simple gas …