A groundbreaking study from Mayo Clinic has unveiled a significant reduction in a specific type of brain cell among individuals with Tourette syndrome. This deficit may explain the uncontrolled motor signals characteristic of the disorder, leading to involuntary tics. Published in Biological Psychiatry, this research is pioneering as it examines individual brain cells from people with Tourette syndrome for the first time. The findings enhance our understanding of how various brain cells might interact and contribute to the symptoms associated with the condition. This work could pave the way for more precise and timely interventions in treating Tourette syndrome.

Dr. Alexej Abyzov, a genomic scientist at Mayo Clinic’s Center for Individualized Medicine, emphasizes that comprehending the alterations in these brain cells and their interactions could revolutionize treatment approaches. Tourette syndrome, a neurodevelopmental disorder often manifesting in childhood, involves repeated involuntary movements and vocalizations. Despite genetic studies identifying risk genes, the biological mechanisms behind the condition have been elusive until now.

The researchers scrutinized over 43,000 individual cells from postmortem brain tissue of both those with and without Tourette syndrome. Their focus was on the basal ganglia, a brain region responsible for movement and behavior control. In each cell, they assessed gene activity and analyzed how changes in gene-control systems might provoke stress and inflammation. Notably, they discovered a 50% decrease in interneurons among individuals with Tourette syndrome. These cells are crucial for calming excessive signals in the brain's movement circuits.

Beyond interneuron deficits, two other types of brain cells exhibited stress responses. Medium spiny neurons, predominant in the basal ganglia and vital for transmitting movement signals, demonstrated reduced energy production. Microglia, the immune cells of the brain, showed signs of inflammation. These responses were closely interconnected, suggesting potential communication between the cells within Tourette syndrome.

Dr. Yifan Wang, co-author of the study, highlights the observation of different brain cell types reacting to stress and possibly communicating in ways that could drive symptoms. The study also indicates that the root cause of brain cell changes in Tourette syndrome might be linked to DNA segments controlling gene activation and deactivation. Dr. Abyzov explains that Tourette patients appear to have the same functional genes as others but lack proper coordination between them.

Looking ahead, the researchers aim to explore how these brain changes evolve over time and seek genetic factors that might clarify the disorder. Conducted in collaboration with Yale University's lab led by Dr. Flora M. Vaccarino, this study marks a significant step forward in unraveling the complexities of Tourette syndrome. By understanding the cellular and genetic underpinnings, future therapies can be more targeted and effective, offering hope for those affected by this challenging condition.