Epilepsy (repeated seizure episodes) occurs in many animal species including dogs (purebred and crossbred). There are many causes, but when the cause is unknown, it is characterized as “idiopathic” epilepsy. Heredity likely plays a role in many dogs with idiopathic epilepsy. The typical age of onset of seizures in dogs with idiopathic epilepsy is 1 to 3 years.
In 2015, the International Veterinary Epilepsy Task Force  published a summary of the scientific literature describing what is known about epilepsy in 21 breeds of dogs including the Shetland Sheepdog. They found three studies on epilepsy in Shelties, all conducted in Japan. The age at seizure onset was primarily between 1 and 1.5 years of age with the seizure frequency varying between one per week to one every 6 months. The gender distribution was nearly 4:1 females vs. males. Sex linked inheritance was ruled out and multifactorial inheritance was thought to be most likely, but a causative gene mutation was not found.
The ASSA supports research that might result in a DNA test to identify epilepsy-causing genetic mutations if they exist in the breed. The Canine Epilepsy Research Consortium (also known as the Canine Epilepsy Network) is a group of scientists who have agreed to collaborate in research efforts to identify epilepsy-causing genetic mutations in dogs. Their work is supported by the AKC Canine Health Foundation, National Institutes of Health (NIH), individual breed clubs and private donations. Click on the following links to learn more about current research on canine epilepsy and how owners of affected dogs might participate and to view past research studies supported by the ASSA.
The Canine Epilepsy Network, is an excellent website with understandable information about epilepsy, its causes, treatments, and living with epileptic dogs. After accessing the main page, click on “Canine Epilepsy Basics”. Another site with links to additional epilepsy resources (at bottom of page) is located at the AKC Canine Health Foundation Epilepsy Research Initiative.
 Hülsmeyer V-I, Fischer A, Mandigers PJJ, et al. International Veterinary Epilepsy Task Force’s current understanding of idiopathic epilepsy of genetic or suspected genetic origin in purebred dogs. BMC Veterinary Research. 2015;11:175. doi:10.1186/s12917-015-0463-0.