Scientists have linked a gene to compulsive behavior - in dogs

Researchers studied Doberman pinschers that curled up into balls, sucking their flanks for hours at a time, and found that the afflicted dogs shared a gene. They describe their findings — the first such gene identified in dogs — in a short report in Molecular Psychiatry. Dr. Nicholas Dodman, director of the animal behavior clinic at the Cummings School of Veterinary Medicine at Tufts University, in North Grafton, Mass., and the lead author of the report, said the findings had broad implications for compulsive disorders in people and animals. Estimates have obsessive-compulsive disorder afflicting anywhere from 2.5% to 8% of the human population. Dr. Dodman and his collaborators searched for a genetic source for this behavior by scanning and comparing the genomes of 94 Doberman pinschers that sucked their flanks, sucked on blankets or engaged in both behaviors with those of 73 Dobermans that did neither. They also studied the pedigrees of all the dogs for complex patterns of inheritance. The researchers identified a spot on canine chromosome 7 that contains the gene CDH2 (Cadherin 2), which showed variation in the genetic code when the sucking and non-sucking dogs were compared. The statistical association led to further investigation to determine for which protein the gene contained instructions. It did for one of the proteins called cadherins, which are found throughout the animal kingdom and are apparently involved in cell alignment, adhesion and signaling. Cadherins have also been recently associated with autism spectrum disorder, which includes repetitive and compulsive behaviors, said Dr. Edward I. Ginns, senior author of the report in Molecular Psychiatry and director of the Molecular Diagnostics Laboratory at the University of Massachusetts Medical School. Some geneticists say that because of the similarity of their genes to those of humans, dogs make an ideal model for studying human behaviors and pathologies.