“WE NEED FAMILIES WITH NORMAL AND AFFECTED MEMBERS. FROM THESE FAMILIES WE HOPE TO IDENTIFY MARKERS LINKED TO EPILEPSY, OR THE MUTATION(S) RESPONSIBLE FOR CAUSING INHERITED SEIZURES.”
Liz Hansen
Project Coordinator of the Canine Epilepsy Project
Genetic researchers studying epilepsy are trying to learn how the disease is inherited in various breeds, including American and English Cocker Spaniels, and are looking for the gene or genes that may cause the disease.
“Knowing the mode of inheritance will make the research easier,” says Barbara Licht, Ph.D., associate professor at Florida State University, who is studying epilepsy in Standard Poodles. “For example, if researchers determine that epilepsy in any given breed is recessive and that only one major gene is involved, then they know they are looking for a single gene and an affected dog has two copies of it. You have a better idea of what you’re looking for.”
Though data is not available on the prevalence of epilepsy in Cocker Spaniels, the incidence among all breeds is about 4 percent, says Liz Hansen, project coordinator of the Canine Epilepsy Project at the University of Missouri.
The Canine Epilepsy Project is part of the Canine Epilepsy Research Consortium, a group of scientists studying the disorder who have agreed to share information, collaborate on papers and release their findings to the public. The project involves a collaborative effort between researchers from the University of Missouri, the University of Minnesota, The Ohio State University and the Animal Health Trust in England.
Grants from the American Kennel Club (AKC) Canine Health Foundation and the National Institutes of Health, as well as individual breed clubs, including the American Spaniel Club, and private donations, help to support the work. The researchers are collecting samples from as many affected dogs and their relatives as possible.
“We need families with normal and affected members,” Hansen says. “From these families we hope to identify markers linked to epilepsy, or the mutation(s) responsible for causing inherited seizures.”
So far, samples from 3,781 dogs representing 72 breeds have been submitted. Of these samples, 624 are from dogs affected with epilepsy –– 20 samples are from affected American Cocker Spaniels. There also is a good representation among other flushing breeds, including English Springer, Welsh Springer and American Water Spaniels.
Flushing spaniels have similar profiles of the disease, Hansen says. “We are not sure just what that means, but it’s notable,” she says. One characteristic noted in flushing spaniels is that more males seem to be affected than females. The hope is that finding the gene in one flushing spaniel breed may help make it easier to find the gene in others.
“Any genetic test developed will be offered to the public at as low a cost as possible,” Hansen says.
Diagnosing Epilepsy
Veterinarians diagnose primary, also known as genetic or idiopathic epilepsy, only after other possible causes of seizures have been ruled out. For example, a seizure can be caused by trauma to the head, a metabolic disorder, poisoning, an infectious disease affecting the central nervous system, or a tumor. Seizures from idiopathic epilepsy can begin at any age, but the common age range is from 1 to 5 years old. Unfortunately, the onset usually comes after a dog is old enough to have been bred.
If a dog has a seizure, an owner should contact his or her veterinarian. The veterinarian should conduct a thorough workup including a physical examination, a complete history, blood work, bile acids assay or ammonia tolerance test to rule out liver problems, and a thyroid function test. If a referral is made to a neurologist, the consultation should include an evaluation of behavior, coordination and reflexes (called a neurological exam) and possible a brain scan (MRI or CT scan), spinal tap, or EEG.”
Epilepsy Treatment
If idiopathic epilepsy is diagnosed, a dog may be treated with anti-convulsant drugs such as phenobarbital or potassium (or sodium) bromide. Since neither of the drugs is without side effects, the veterinarian and owner might choose to wait until seizures become more frequent or prolonged before starting an epileptic dog on them.
Dawn Boothe, D.V.M., Ph.D., associate professor of veterinary physiology and pharmacology at Texas A&M University, has completed a study funded by the AKC Canine Health Foundation that examined the safety and efficacy of phenobarbital vs. bromide. She found that both drugs have short-term side effects, which include grogginess, vomiting and increased hunger, thirst and urination. With the exception of vomiting, the side effects diminish with both drugs. Some dogs taking bromide were still vomiting six months later.
Phenobarbital was more effective than bromide in eliminating and shortening the duration of seizures. Thus, for many dogs, phenobarbital may be the first choice for an anti-seizure medication. Though the study did not look at long-term effects of using either drug, phenobarbital can damage the liver with prolonged use. Also, phenobarbital more so than bromide interacts with many other drugs. For that reason, bromide might be a better first choice for older dogs or those on other drugs, Boothe says.
Benefits of Genetic Research
The benefits for breeders of development and availability of an affordable DNA test for epilepsy are tremendous. A DNA test would identify carriers and help to define safe breeding practices that do not necessarily end a dog’s breeding career.
If epilepsy in American or English Cockers is determined to be a recessive trait (or under some circumstances, a trait involving more than one gene), then carriers could be bred to dogs that have tested normal without producing offspring that will end up with epilepsy. Since half the offspring of such breeding would be carriers, DNA testing on offspring before breeding them would be essential.
“No one is recommending neutering or spaying all carriers,” says Anita Oberbauer, Ph.D, professor of animal science at the University of California-Davis, who is studying epilepsy in the Belgian Sheepdog, Belgian Tervuren, English Mastiff, Giant Schnauzer and Poodle. “A breed is not a single gene. Breeders with carriers in their lines will be able to maximize the diversity of the gene pool using DNA testing without taking the risk of producing affected dogs. You can keep the desirable traits you are breeding for.”
Another potential benefit of the genetic research under way on canine epilepsy is that it may help researchers develop treatments for different forms of epilepsy. “Right now, since we don’t know what is going wrong at the cell level to cause seizures, our treatment is purely symptomatic,” says Dennis O’Brien, D.V.M., Ph.D., one of the University of Missouri researchers working on the Canine Epilepsy Project. “If we can identify what the underlying cause is, be it an ion channel mutation or an enzyme deficiency, we may be able to develop therapies that attack the problem at its source.”
What is Epilepsy?
Simply put, epilepsy is repeated seizures. It may be caused by a condition such as a brain tumor, trauma or a stroke. When that’s the case, it’s referred to as secondary or symptomatic epilepsy. If no cause is found for repeated seizures, it is known as primary or idiopathic epilepsy. Idiopathic epilepsy appears to be inherited; that is, it appears to be caused by a mutation of a specific gene or genes.
Researchers, including those with the Canine Epilepsy Project, the University of California-Davis and Florida State University, are trying to learn in which breeds epilepsy is inherited, how it is inherited, and which genes are involved. To make a complex puzzle even more complicated, the answers to those questions might be different for each breed.
How Cocker Spaniel Breeders Can Help?
The Canine Epilepsy Project needs more genetic samples from American and English Cocker Spaniels.
“If we don’t have the samples to work with, we won’t make any progress,” says Liz Hansen, project coordinator of the Canine Epilepsy Project. The project is looking for blood samples and pedigrees from affected dogs and their relatives.
Samples, taken by veterinarians, from affected dogs should be accompanied by a seizure survey. All forms can be downloaded from www.canine-epilepsy.net. If you do not have Internet access, contact Liz Hansen at (573) 884-3712. All information collected is kept strictly confidential. The Canine Epilepsy Project’s Web site also provides extensive educational information about epilepsy.
Epilepsy Sources
Dawn Boothe, D.V.M., Ph.D.,Department of Veterinary Physiology and Pharmacology,College of Veterinary Medicine, Texas A&M University. Phone 979-845-9368; E-mail: This e-mail address is being protected from spambots, you need JavaScript enabled to view it
Liz Hansen, Project Coordinator, Canine Epilepsy Project, Animal Molecular Genetics Lab321 Connway Hall, University of Missouri, Columbia, MO 65211 Phone: 573-884-3712; Department fax: 573-884-5414; E-mail: This e-mail address is being protected from spambots, you need JavaScript enabled to view it or http://www.canine-epilepsy.net
Barbara Licht, Ph.D., The Poodle Epilepsy Project,Department of Psychology,Florida State University,Tallahassee, FL 32306-1270. Phone: (850) 644-6272; Fax: (850) 644-7739; Email: This e-mail address is being protected from spambots, you need JavaScript enabled to view it or http://www.geocities.com/Heartland/Garden/1686/
Anita Oberbauer, Ph.D.,Canine Genetic Analysis Program, Department of Animal Science, University of California, Davis, One Shields Ave., Davis, CA 95616. Phone: (530) 752-4997; Fax: (530) 752-0175; Email: This e-mail address is being protected from spambots, you need JavaScript enabled to view it or http://cgap.ucdavis.edu
Dennis O’Brien, D.V.M., Ph.D., Associate Professor of Veterinary Neurology, University of Missouri, 379 East Campus Drive, Columbia, MO 65211. Phone: 573-882-7821; E-mail: This e-mail address is being protected from spambots, you need JavaScript enabled to view it
Used with permission from the Purina Pro Club Cocker Spaniel Update, Nestlé Purina PetCare Company.
The 2009 ASC Annual Flushing Spaniel Show