Dozens of genes tied to OCD and tic disorders discovered

A Rutgers-led international research team has identified 36 genes associated with obsessive-compulsive disorder (OCD) and chronic tic disorders, marking a significant advancement in understanding these conditions. Before this study, published in Nature Neuroscience, scientists had identified only a few genetic links, each individually tied to either OCD or tic disorders. The new findings provide a comprehensive biological understanding of these conditions and suggest potential treatment avenues.

Gary Heiman, a professor in Rutgers' Department of Genetics, emphasized that the research dramatically expands the catalog of shared risk genes and reveals biological connections with autism and schizophrenia. OCD is characterized by intrusive thoughts and repetitive behaviors, while tic disorders, including Tourette syndrome, involve uncontrollable movements or vocalizations. Both conditions often co-occur in individuals and families and affect millions globally, particularly in childhood.

Previously, only a few strong genes were known, limiting pharmaceutical prospects for developing treatments. With over 30 new targets identified, there are now more opportunities for drug development. The study analyzed DNA from nearly 4,000 individuals diagnosed with OCD, tic disorders, or both conditions, focusing on rare mutations that disrupt genes crucial for brain function. Many of the newly discovered genes are shared between OCD and tic disorders, explaining their co-occurrence in individuals and families.

These genes do not act independently but rather in networks, making it easier to design new therapies. Additionally, several of the identified genes were previously linked to autism and schizophrenia, reinforcing the idea that multiple psychiatric conditions may stem from related disruptions in brain development and communication. The genes identified influence neurotransmitter movement across brain circuits, providing insight into the underlying biological mechanisms.

The study's findings suggest that many risk genes are active in brain regions involved in movement, decision-making, and habit formation, such as the cortex and striatum. Researchers used whole-exome sequencing, a technique that examines gene sections instructing protein production, to analyze genetic data from over 30 research teams across the U.S., Canada, Europe, South Korea, and South America.

The collaboration combined genetic data from affected individuals, their parents, and healthy controls, identifying new mutations specific to the children that likely play a role in the disorders.

Heiman and co-author Jay Tischfield, a pioneer in Tourette syndrome research, highlighted that the study wouldn't have been possible without the long-term commitment of families who volunteered their DNA samples. Many families were recruited through the New Jersey Center for Tourette Syndrome and Associated Disorders and other research programs worldwide. Their contributions enabled the collection of valuable genetic data that modern sequencing technologies can now analyze.

Rutgers researchers involved in the study included Jinchuan Xing, Max Tischfield, Joshua Thackray, Cara Nasello, and Danea Glover. The study represents a significant step forward, offering a clearer understanding of the disorders' causes and providing numerous directions for developing improved treatments.