Background: There is a lack of data on idiopathic epilepsy (IE) in Border Collies (BCs) in the veterinary literature. Hypothesis: Genetic epilepsy occurs in BCs and is frequently characterized by a severe clinical course and poor response to medical treatment.Animals: Forty-nine BCs diagnosed with IE. Methods: Medical records, seizure data, treatment data, and pedigree information of affected dogs were collected. Cases were classified phenotypically as affected or not affected; mild, moderate, or severe clinical course; active epilepsy (AE) or remission; and drug resistant or not drug resistant.Results: Clinical manifestations were classified as having a moderate (33%) or severe clinical course (49%), characterized by a high prevalence of cluster seizures and status epilepticus. Survival time was significantly decreased in dogs o2 years of age at seizure onset, and in dogs with a severe clinical course. Drug resistance was apparent in 71% of 24 dogs treated with 2 antiepileptic drugs. The epilepsy remission rate was 18%. Median age at onset was significantly higher and initial seizure frequency was significantly lower in dogs with remission compared with dogs with AE. Pedigree analyses indicated a strong genetic founder effect in the appearance of epilepsy, resembling autosomal recessive inheritance.Conclusion and Clinical Importance: The present study confirms the occurrence of genetically mediated epilepsy with a frequent severe clinical course and drug resistance in BCs. The results provide information about the long-term prognosis of IE in BCs for veterinarians and concerned owners, and may benefit breeders as well.

Background: Idiopathic epilepsy (IE) in Australian Shepherds (ASs) occurs worldwide but there is a lack of description of the epilepsy syndrome in this breed. The ABCB1-1D mutation is more prevalent in ASs than in many other dog breeds.Hypothesis: Australian Shepherds suffer from a poorly controlled IE syndrome with prevailing severe courses. Seizure control and ABCB1-1D mutation might be related in this breed.Animals: Fifty ASs diagnosed with IE and 50 unaffected ASs. Methods: Predominant study design is a longitudinal cohort study. Pedigrees, medical records, seizure, and treatment data of ASs with IE were analyzed descriptively. Sex, color, and the ABCB1-1D genotype were compared between case and control groups and ASs with poorly or well-controlled seizures. Differences in survival times were assessed by logrank tests and Cox regression analysis.Results: Idiopathic epilepsy in ASs is dominated by moderate and severe clinical courses with the occurrence of cluster seizures and status epilepticus and a high seizure frequency. Poor seizure control and a high initial seizure frequency ( ! 10 seizure days/first 6 months) are associated with shorter survival times (P < .05). Poor seizure control, unrelated to the ABCB1(MDR1) genotype, is evident in 56% of epileptic ASs. Pedigree analysis suggests a genetic basis.Conclusion and Clinical Importance: Frequent severe clinical courses, poor seizure control unrelated to the ABCB1 (MDR1) genotype, and a young age at death compromise animal welfare and warrant further genetic studies to unravel the underlaying molecular mechanisms of IE and seizure control in the breed.

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