Researchers identify genetic marker for OCD

Scientists have identified a genetic marker that may be associated with the development of obsessive compulsive disorder (OCD).

OCD affects an estimated 2 percent of the population and is one of the least understood mental illnesses. The condition is marked by thoughts and images that chronically intrude in the mind and by repetitive behaviors aimed at reducing the associated anxiety. The standard treatments – such as selective serotonin reuptake inhibitor (SSRI) medications and behavioral psychotherapy – are about 60 to 70 percent effective, but they don’t help all patients and only treat disease symptoms.

Identifying a genetic marker for OCD could help scientists develop more effective therapies for the condition.

“Like most other medical and psychological conditions, we need to understand what causes conditions, so we can develop real and rational treatments for these conditions and/or prevention,” lead study author Dr. Gerald Nestadt, a professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, told FoxNews.com. “That’s why it’s important to study or identify genetic causes, if there are any.”

In collaboration with seven universities, Nestadt and his colleagues conducted a genome-wide association study of 1,400 people with OCD. For their control group, researchers studied the genomes of 1,000 parents of OCD patients. Researchers looked for an association between the condition and a particular genetic marker. They were able to identify a genetic marker located near a gene that encodes the protein tyrosine phosphokinase. In the study, more people in the OCD group had the genetic marker, compared to those in the control group.

A genetic marker typically is not the specific abnormality, but tells researchers something very close to the marker is the variant of interest, Nestadt said. Researchers note that, while they have a found a genetic marker, they have yet to discover the exact variant associated with OCD and therefore do not know the exact genetic cause of the disease.

“That is the goal. The idea is that if we know what chemical or protein is affected in the condition, then we can work out what problem is in the brain that causes the condition and the next step is to find a pharmaceutical that changes that or affects that so as to improve the condition,” said Nestadt, who is also director of Johns Hopkins’ Obsessive-Compulsive Disorder program.

While there has been significant genetic research into other physical diseases, such as diabetes and heart disease, OCD has been less studied. Nestadt believes it’s because there are fewer researchers in the field of OCD genetics, as well as less availability of funds and a lack of understanding of the disease.

“We all have friends who say, ‘Well, I’m a little OCD.’ I think that has actually hurt the individuals who truly suffer from the condition— everybody thinks of it as a joke or not serious or not disabling. If you seriously meet someone who has OCD and see what life is like, you’ll absolutely change your mind,” he said.

The only known risk factor for OCD is having a family member with the disease. In previous research, Nestadt had found that 40 percent of people with OCD had a first-degree relative with the disease.

The team’s findings, published in the journal Molecular Psychiatry, could lead to further genome research that could potentially identify the exact cause of the mental illness, as well as new treatments.

“We’re not, today, going to change the course of the disorder for someone with OCD, but we absolutely have the hope and expectation that in 10 to 15 years, things will be very different, and certainly for the individual’s children,” Nestadt said.