Epilepsy in Border Collies: clinical manifestation, outcome, and mode of inheritance.

Abstract

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 < 2 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.