14 DAY TRIAL // Many dog breeds have a high susceptibility to developing compulsive disorders in their lifetimes. The condition is not only limited to certain species, as individual members of other dog types can develop it as well. Now, a scientific group has managed to identify the gene that is believed to be responsible for this type of behavior. According to the experts, it resides on a chromosome 7 locus. Details of the finding appear in the January 2010 issue of the respected scientific journal Molecular Psychiatry.
The work was only made possible by a collaboration between experts at the TU Cummings School of Veterinary Medicine Behavior Service, the University of Massachusetts Medical School Program in Medical Genetics, and experts at the Massachusetts Institute of Technology (MIT) Broad Institute. The team says that compulsive disorders, defined as repeated, time-consuming behaviors, tend to affect about two percent of the world's human population. In the case of dogs, breeds such as Dobermans and Bull Terriers are the most affected, on average, ScienceDaily reports.
Using the Broad Institute's canine Affymetrix genotyping array, the experts were able to begin a genome-wide association study on this issue in 2007. Before that, experts at the Tufts University Cummings School of Veterinary Medicine gathered blood samples from healthy Dobermans, as well as from Dobermans that had compulsive disorders, including flank- and/or blanket-sucking behaviors. The effort determined that the cadherin-2 gene, also known as CDH2, was the headquarters of the chromosome 7 locus that increased a dog's chances of developing OCD.
“The CDH2 gene is expressed in the hippocampus, a brain region suspected to be involved in OCD. In addition, this gene oversees structures and processes that are possibly instrumental in propagating compulsive behaviors – for example, the formation and proper functioning of glutamate receptors,” Dr. Nicholas Dodman, a professor of clinical sciences at the CSVM, and also the lead author of the new study, explains.
“The occurrence of repetitive behaviors and similarities in response to drug treatments in both canine CCD and human OCD suggests that common pathways are involved. […] Our finding will lead to a better understanding of the biology of compulsive disorder and facilitate development of genetic tests, enabling earlier interventions and even treatment or prevention of compulsive disorders in at-risk canines and humans,” the head of the UMass Medical School Program in Medical Genetics, Edward Ginns, PhD, MD, says. He is also a professor of clinical pathology, neurology, pediatrics, psychiatry and neuroscience at the university.