Prevalence and heritability of symptomatic syringomyelia in Cavalier King Charles Spaniels and long-term outcome in symptomatic and asymptomatic littermates

J Vet Intern Med. 2015 Jan;29(1):243-50. doi: 10.1111/jvim.12475. Epub 2014 Oct 10.


Background: Syringomyelia (SM) is common in the Cavalier King Charles Spaniel (CKCS). Dogs with syringes express clinical signs or might be clinically silent.

Objectives: To investigate the prevalence and heritability of symptomatic SM, the association between clinical signs and magnetic resonance imaging (MRI) findings, and long-term outcome.

Animals: All CKCS registered in the Danish Kennel Club in 2001 (n = 240).

Methods: A cross-sectional questionnaire-based prevalence study validated by telephone interviews and clinically investigated clinical signs of SM. Dogs were 6 years at the time of investigation. A prospective observational litter study including clinical investigations, MRI and 5-year follow-up of symptomatic and asymptomatic siblings. Heritability was estimated based on the scale of liability in the study population and litter cohort.

Results: The cross-sectional study estimated a prevalence of symptomatic SM at 15.4% in the population. Thirteen symptomatic and 9 asymptomatic siblings participated in the litter study. Spinal cord syringes were confirmed in 21 of 22 littermates (95%). Syrinx diameter and mean syrinx : spinal cord ratio were significantly correlated with clinical signs (P < .01). Estimated heritability of symptomatic SM was 0.81. Symptomatic SM motivated euthanasia in 20%. Dogs with syringes, which expressed no clinical signs at the age of 6, remained asymptomatic in 14/15 cases (93%).

Conclusions and clinical importance: The prevalence of symptomatic SM is high and genetics have a high impact on clinical disease expression. Further investigations of factors influencing the outbreak threshold of clinical signs of SM are desirable.

Keywords: Chiari-like malformation; Dog; Epidemiologic; Genetics; Magnetic resonance imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging
  • Animals
  • Cohort Studies
  • Cross-Sectional Studies
  • Data Collection
  • Denmark / epidemiology
  • Dog Diseases / diagnostic imaging
  • Dog Diseases / epidemiology
  • Dog Diseases / genetics*
  • Dogs
  • Female
  • Interviews as Topic
  • Magnetic Resonance Imaging / veterinary
  • Male
  • Prevalence
  • Radiography
  • Syringomyelia / diagnostic imaging
  • Syringomyelia / epidemiology
  • Syringomyelia / genetics
  • Syringomyelia / veterinary*