Chiari-like Malformation and Syringomyelia in The Cavalier King Charles Spaniel
UPDATE—December 2008  

Since the very important International Conference held in Rugby, England in November  2006, research has continued into this condition.  The Cavalier King Charles Club of Canada is very proud to be involved in two studies taking place in Canada.   

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The primary investigators were Dr. K. Wolfe DMV (at OVC for 3 year Doctor of Veterinary Science program) Dr. Roberto Poma DMV, DVSc, ACVIM Neurology, Assistant Professor Department of Clinical Studies, and Dr. Stephanie Nykamp DVM, Neuro-Radiologist 

Included in this study was the Brainstem Auditory Evoked Responses (BAER) hearing test. 

Results from this testing include:

• Does the dog have Chiari-like malformation of the caudal skull.
• Is there a dilatation of the central canal of the spinal cord
• Is Syringomyelia present and the location in the spinal cord
• Is there muciod material in either ear (PSOM)

All dogs were given a classification grade. This is important to breeders following the breeding recommendations from the International Conference held in Nov. 2006. 

Written & submitted by Judith Weir

STUDY NOW COMPLETE

The Syringomyelia Study Project at the Ontario Veterinary College has been successfully completed with a total of 50 Cavaliers MRI scanned. 

Dr. Poma was instrumental in writing the proposal for our Study to the Pet Trust committee at OVC in Guelph to enable our members to have an affordable MRI of full spinal scans. 

Thank you Dr. Poma, Dr. Nykamp, and Dr. Wolfe for your commitment, and hard work to this very important research of Chairi-like malformation and Syringomyelia. 

Blood from each Cavalier was sent to Sainte Justine Hospital at the University of Montreal for DNA for the Genome Study. 

Results were also sent to Penny Knowler and Dr. Sarah Blott in the UK. 

Thank you to all our Club members and their wonderful Cavaliers for participating in this important study project.  We look forward to a completed report from all the information collected by Dr. Poma and Dr. Wolfe in the near future. 

Dr. Wolfe is working hard on her Thesis and we wish her GOOD LUCK.

LOW COST MRI’S

The OVC are unable to continue with the study this year but we feel that continuing with the research by making lost cost MRI’s available is very important for our Cavaliers to eliminate this devastating condition. 

The Matheson Veterinary Services Clinic in Mississauga will be offering one Saturday a month to MRI six dogs.  There will be more information and a form to fill out on the website.  Mary Beth Squirell will be looking after the scheduling.

There are three board certified Veterinary Anaesthetists at the clinic and Dr. Nykamp from OVC will continue to read the scans which will be sent directly to her.  Dr. Nykamp will send a written report and the clinic will provide a CD of the scan before leaving the clinic. 

Researchers are very interested in collecting information on Cavaliers five years and older and their siblings……more on this later. 

Written & Submitted by Joan MacIntyre, Chairperson Health& Education Committee 

GENOME STUDY—CHU SAINTE JUSTINE RESEARCH CENTER, MONTREAL, QUEBEC 
 

The following is a summary sent to Health and Education Committee by Dr. Zoha Kibar.  

“Genetic studies of Chiari- like Malformation with Syringomyelia in the Cavalier King Charles Spaniels  

      Chiari-like malformation (CM) is a condition characterized by disparity in size between the brain (too big) and the caudal fossa (too small) such that the back of the brain is pushed into the vertebral canal obstructing fluid movement in and around the brain. A consequence of this is syringomyelia (SM) where fluid filled cavities develop within the spinal cord. CM and SM can cause a variety of clinical signs of which the most important is pain. This can vary in severity from mild pain to more devastating neuropathic pain which includes persistent scratching at one side of the shoulder/neck. Some dogs have other neurological deficits including paresis, poor coordination (ataxia) and spinal curvature (scoliosis). Pedigree and heritability studies in the Cavalier king Charles Spaniels (CKCS) suggest the involvement of genetic factors in the etiology of this disease. The underlying pathogenic mechanisms remain poorly understood.  

      We have initiated a large collaborative study to identify and characterize the gene(s) responsible for CM/SM in the CKCS breed. The lead investigator in this study is Dr. Zoha Kibar from the CHU Sainte Justine Hospital at the University of Montreal. The co-investigators are: Drs Guy Rouleau, and Marie-Pierre Dube, from the University of Montreal, Dr. Clare Rusbridge, and Mrs. Penny Knowler, from the Stone Lion Veterinary Centre in London, UK, and Dr. Sarah Blott from the Animal Health Trust, UK. This team brings together significant expertise in the clinical and biological aspects of CM and associated SM, as well as in genetics and statistical analysis of complex traits.  

      We have constructed a genealogy of more than 10,600 related CKCS dogs spanning 24 generations from over 600 MRI confirmed dogs and established a wide DNA collection of over 1,500 samples. We completed a whole-genome scan in 173 CKCS dogs selected based on SM-affected status and familial relationship. Genetic analysis identified six genomic regions that could harbor the CM/SM gene(s). We are currently investigating these regions by additional genetic studies in a larger sample size. We will conduct a new whole genome scan using the innovative canine SNP (or single nucleotide polymorphisms) genotyping technology.  We will next narrow down the candidate genetic interval(s) identified in both genome scans using genetic studies in the CKCS and other related breeds affected with CM/SM. Once the candidate genomic region(s) have been well defined, we will use the positional candidate gene approach to identify the defective gene(s) in CM/SM.  

As an imminent outcome, our study of identifying the gene(s) responsible for CM/SM will allow the development of a genetic test to identify carriers and devise breeding strategies to reduce or eliminate this devastating condition in the CKCS and other affected breeds. These studies will also help better understand the underlying molecular and cellular pathogenic mechanisms for better diagnosis, prognosis and clinical management of CM and associated SM.”

Written & Submitted by Judith Weir