Canine OCD order may be model for humans

If obsessive-compulsive disorder (OCD) is a genetic illness, research into OCD in dogs may provide information about the source of human OCD.

This year's annual International Conference on the Status of Plant and Animal Genome Research took place Jan. 9-13 at the Town and Country Hotel in San Diego, and the Jan. 10 Cat and Dog Workshop included the presentation "Shared Genetics of Obsessive Compulsive Disorder in Dogs and Humans" which was given by Elinor Karlsson of the University of Massachusetts medical school.

Dogs with canine compulsive disorder tend to exhibit symptoms at six to seven months of age while humans with obsessive-compulsive disorder are often adolescents when they are determined to have OCD. "In both humans and dogs the age of onset is very similar," Karlsson said.

OCD has a highly polygenic architecture which complicates the identification of genetic risk factors with current sample sizes. "They haven't been able to find any genome-wide significant loci," Karlsson said.

Doberman pinschers, German shepherds, Jack Russell terriers, and Shetland sheepdogs are the breeds which seem to have the highest occurrences of canine OCD. The research evaluating affected and control dogs began with Dobermans and then moved to cross-breed studies.

A gene found in canine chromosome 7 and human chromosome 18 may be the key to identifying OCD, since a variation was found in all of the affected Dobermans. "There was one very striking one," Karlsson said.

The study is continuing with additional dogs to determine the variations leading to the phenotypes (observable traits of a gene) of OCD. "We're going to have to produce the phenotypes," Karlsson said.