Utrecht University’s Faculty of Veterinary Medicine has developed DNA tests to track genetic nerve disorders in the kooikerhondje and the Frisian stabij. Breeders of these Dutch breeds can have their dog tested to see if it is a carrier of a specific gene, in order to prevent the breeding of puppies with the disease.
Over the past few years, several litters of Frisian stabij puppies have had individuals that develop severe neurological symptoms at a young age. These pups display compulsive behaviour, turning in circles, pushing against walls, constantly sniffing or walking backwards. They also have reduced consciousness. “The most remarkable symptom is that the pups constantly turn in circles”, says researcher Peter Leegwater. “Unfortunately, there is nothing we can do about it, and eventually we have to put the pups to sleep.”
Researchers at the Faculty of Veterinary Medicine’s University Clinic for Companion Animal Health have developed a DNA test to track dogs that are carriers of heritable diseases. For example, the compulsive behaviour in the Frisian stabij puppies was caused by a DNA defect that resulted in defects in a certain protein. “We now know which protein it is, and what it does”, says Leegwater. “The protein is responsible for the reuptake of a neurotransmitter in a nerve cell after stimulus transfer. The stimulus should stop after the signal has been transmitted, but due to the defect the signal continues to transmit the stimulus.” The study was financed in part by the Meijer Boekbinder Fund.
The researchers in Utrecht have also uncovered the cause of a neurological defect in Dutch kooikerhondjes. Kooiker pups occasionally develop heritidary necrotic myelopathy, a chronic progressive disease. “The condition begins with the paralysis of the hind legs when the pups reach the age of three to 12 months. It is caused by erosion of the white tissue in the spinal cord and damage to the nerve fibres. No treatment is available for this fatal condition”, Leegwater explains. Scientists do not yet know which gene is responsible, but they have narrowed it down to a section of a chromosome. With this knowledge, they were able to develop a DNA test to test if breeding dogs carry the gene.
With proper observation and modern DNA techniques, the researchers will soon be able to trace the genetic components that cause this disease, and in the near future it will be possible to unravel the genetic foundations of more common and complex diseases. The researchers believe that the release of ever-more DNA data will make it possible to implement a more rational breeding policy, which will result in improved animal welfare. That is also one of the goals of the Meijer Boekbinder Fund and the companion animal sector’s ‘Fair Breeding’ project plan.
The Netherlands Association of Stabij and Wetterhoun Breeders, the Netherlands Kooikerhondje Association, the Raad van Beheer op Kynologisch gebied in Nederland (Dutch Kennel Club) and the Faculty of Veterinary Medicine’s Companion Animals Genetics Expertise Centre are all closely involved in the research.
See also the Companion Animals Genetics Expertise Centre website.