Characterization and mode of inheritance of a paroxysmal dyskinesia in Chinook dogs

J Vet Intern Med. Nov-Dec 2010;24(6):1305-13. doi: 10.1111/j.1939-1676.2010.0629.x.

Abstract

Background: Paroxysmal dyskinesias are episodes of abnormal, involuntary movement or muscle tone, distinguished from seizures by the character of the episode and lack of seizure activity on ictal EEG.

Hypothesis: Paroxysmal dyskinesia is an inherited, autosomal recessive disorder in Chinook dogs.

Animals: Families of Chinook dogs with paroxysmal dyskinesia.

Methods: Pedigrees and medical histories were reviewed for 299 Chinook dogs. A family of 51 dogs was used for analysis. Episodes were classified as seizures, paroxysmal dyskinesia, or unknown, and segregation analysis was performed.

Results: Paroxysmal dyskinesia was identified in 16 of 51 dogs and characterized by an inability to stand or ambulate, head tremors, and involuntary flexion of 1 or multiple limbs, without autonomic signs or loss of consciousness. Episode duration varied from minutes to an hour. Inter-ictal EEGs recorded on 2 dogs with dyskinesia were normal. Three dogs with dyskinesia also had generalized tonic-clonic seizures. One of 51 dogs had episodes of undetermined type. Phenotype was unknown for 6 of 51 dogs, and 28 dogs were unaffected. Segregation was consistent with an autosomal recessive trait.

Conclusions and clinical importance: This movement disorder is prevalent in the Chinook breed, and consistent with a partially penetrant autosomal recessive or polygenic trait. Insufficient evidence exists for definitive localization; episodes may be of basal nuclear origin, but atypical seizures and muscle membrane disorders remain possible etiologies. The generalized seizures may be a variant phenotype of the same mutation that results in dyskinesia, or the 2 syndromes may be independent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chorea / genetics
  • Chorea / veterinary*
  • Dog Diseases / genetics*
  • Dogs
  • Genetic Predisposition to Disease*
  • Pedigree