University of Missouri Research Project*
Epilepsy is one of the most common diseases of the nervous system in dogs. The effects of repeated seizures can be devastating physically for the affected dogs and emotionally for the people who care for them. Epilepsy is known to be inherited in several breeds, and genetics is thought to play a key role in many others. In preliminary studies of epilepsy in a family of Standard Schnauzers, we found DNA markers which appear to be associated with the disease. Near these markers on human and mouse chromosomes are genes for potassium channels. The potassium channel genes are logical places for an epilepsy-causing mutation, so we are currently looking for the responsible mutation within these genes. If we find the responsible mutation, we can create a DNA marker that will allow Standard Schnauzer breeders to identify puppies destined to develop epilepsy. In addition, the marker will identify epilepsy carriers, enabling Standard Schnauzer breeders to avoid matings that will produce epileptic offspring. The promising results from this preliminary study have prompted us to seek funds to complete the Standard Schnauzer study and to initiate a similar study of epilepsy in English Springer Spaniels.
University of Minnesota Research Project*
We propose to develop a micro satellite screening test for epilepsy in English Springer Spaniels, Vizslas, and Beagles. Epileptic dogs will be identified, and the mode(s) of inheritance determined in each breed. Owner questionnaires will be conducted to classify the phenotype of each individual in extended three-generation pedigrees to determine the mode(s) of inheritance by pedigree analysis. Genetic linkage analysis using micro satellite markers will be used to attempt to find a DNA marker linked to canine epilepsy in one or more of the breeds. A number of linked markers will hopefully be identified, and a linkage map of these markers will be determined from somatic cell hybrid panels or the developed and emerging canine linkage map. Comparative mapping across species may allow prediction of candidate genes based from the syntenic chromosomal position in humans. Affected pedigrees and epileptic kindred from the study breeds will be genotyped and the linkage data examined to determine if genetic heterogeneity exists within and between breeds. Dogs with predicted disease status will be followed to assess the accuracy of disease prediction based on the linkage test.
* The above abstracts describe the two new epilepsy research projects approved for funding in December 1998 by the AKC Canine Health Foundation.
University of Minnesota Research Project
We propose to develop a genetic screening test for canine epilepsy, a serious late-onset seizure disorder affecting a large number of breeds.
The onset of seizures in dogs with epilepsy is typically from one to five years of age. The late onset means that often a dog has already been bred before it is known to be affected. In some individuals, seizures are well controlled with anticonvulsant medications, but a significant number of dogs have “refractory” seizures needing high doses of medications to achieve control. The severity of seizures may be such that the owner elects to have the dog euthanized. A genetic test for epilepsy would allow breeders to screen potential breeding animals for this common, frustrating, and potentially devastating disorder prior to making breeding decisions. We propose to determine the mode of inheritance for epilepsy in 3 breeds( English Springer Spaniels, Vizslas, and Beagles) and to use genetic markers to develop a screening linkage test for predicting epilepsy in these breeds. This approach to identifying the region of the canine genome containing the defective gene will ultimately lead to the prediction of candidate genes that can be characterized to define the precise defect responsible.