Two new studies take a new view of obsessive compulsive disorder (OCD) and Tourette syndrome (TS). In the studies, researchers have identified gene variants that contribute to the risks of developing both neurological disorders.
Challenge of OCD and TS
“Previous studies of these disorders have demonstrated that both TS and OCD are strongly inheritable and may have shared genetic risk factors, but identification of specific genes has been a huge challenge,” noted Jeremiah Scharf, MD, PhD, of the Psychiatric and Neurodevelopmental Genetics Unit ) in the Massachusetts General Hospital (MGH Departments of Psychiatry and Neurology.
No single genetic source
TS is characterized by muscle and vocal tics. It often occurs alongside OCD which is a mental illness characterized by repetitive behaviors and anxiety producing thoughts. These new studies however have identified several locations on the human chromosome that may contribute to the development of these conditions.
A number of likely influences
In the TS study, Scharf and team compare genomes of more than 1200 people with the disorder with the genomes of nearly 5000 healthy people. They performed a genome wide association study (GWA) by scanning hundreds of thousands of genetic variants to see if any were more common in the people with the disorder. While no single genetic signal was found, they did find an unusually high number of influence levels of gene expression in the frontal lobe of the brain.
For the OCD study, Scharf again used GWAS to analyze the genetic makeup of people with OCD. Again, no clear gene, but they found a candidate near a gene called BTBD3. “Now that we have this data for Tourette syndrome and OCD, we can work with investigators who are studying those other diseases to try to see what we can learn about what variants are shared between different neurodevelopment disorders,” concluded Scharf.
Source: Molecular Psychiatry