Genetic Code of OCD and Tourette Syndrome Decoded

The human brain's complex developmental journey, which begins in the mother's womb and continues after birth, has witnessed a historical discovery regarding the biological origins of neurological and psychiatric disorders. Led by Rutgers University and published in the prestigious medical journal Nature Neuroscience, the research has cracked the genetic codes of chronic tic disorders such as Tourette syndrome and obsessive-compulsive disorder (OCD), which affect a large segment of society.

While only four "high-confidence" genes directly associated with these two hereditary conditions were previously known, the latest study has increased the number of genes that directly raise disease risk to 36.

EXOME DATA AND BRAIN MAPS OF 4,000 PEOPLE EXAMINED

In the comprehensive clinical research, the protein-coding DNA sequences (exome data) of nearly 4,000 individuals diagnosed with OCD or tic disorders, along with their parents, were analyzed. Comparisons made with brain maps obtained from chimpanzees and mice, in addition to humans, revealed the neural architecture behind the conditions.

The data confirmed that 30 of the 36 identified risk genes function jointly in both OCD and Tourette cases. The occurrence of obsessive behaviors in 50% of patients with tic disorders, and a history of tics in 30% of OCD patients, substantiated the high genetic overlap between the two conditions.

BRAIN'S IMPULSE AND MOVEMENT CENTERS TARGETED

The findings indicate that these conditions stem from dysfunction in the brain's broad circuit called the "cortico-striato-thalamo-cortical" network, which governs impulse control, movement, decision-making, and data processing.

It was documented that risk genes show high levels of activation before and after birth in the "cortex," responsible for thinking and memory; the "striatum," our decision-making center; the "thalamus," a signal relay station; and the "cerebellum," the balance coordinator. Additionally, specific excitatory neurons that facilitate communication between brain regions were found to play a key role in these diseases.

SHARED BIOLOGICAL LINK WITH AUTISM AND SCHIZOPHRENIA

Researchers identified that the defined risk genes are not limited to OCD and Tourette alone, but also share strong links with other neurodevelopmental conditions such as autism spectrum disorder, developmental delays, and schizophrenia. It was determined that the identified genes do not act in isolation but operate in networks, increasing the risk of disease by an average of 57-fold, and up to 210-fold in extreme cases.

Prof. Dr. Jay Tischfield, one of the senior authors of the study, stated that the pharmaceutical industry could not develop new treatments in the past due to the limited number of known genes, evaluating: "We now have more than 30 targets and the networks formed by these genes. This opens a brand-new chapter in medical history for the development of personalized and targeted new medications."