In light of a recent research report that showed the chances of getting a puppy with a serious, life threatening disease, we were curious to know:

How much risk are you willing to take if you know the odds of buying a puppy with a serious genetic disorder?

The report we are referring to was produced in an effort to reduce the incidence of Cavalier King Charles Spaniels affected with symptoms of syringomyelia, life threatening, costly-to-treat, nervous system disorder that affect many small toy breeds. A guideline of breeding recommendations were created in response to requests from breeders.

The list of recommendations were:

1. Both the sire and the dam of a proposed mating are screened

2. Offspring of any mating should also be MRI screened before breeding

3. Dogs screened before 2.5 years old should be screen a second time when older

4. Dogs are to be screened from 6 months of age

5. If a limited ("mini" ) MRI screen is performed:

(a) the minimum area covered is from approximately the level of the thalamus / corpus callosum to cervical vertebrae 5 (C5)

(b) Both TW1 and TW2 = sagittal images are obtained in addition to TW1 and /or TW2 transverse images through the upper cervical spinal cord

(c) An assessment is also made for presence/absence of ear disease and ventricular enlargement

6. Interpretation of images is made by Diplomate level radiologists, neurologists and, in special circumstances, by orthopedic surgeons with recognized expertise in this area

Cavalier King Charles Spaniels proposed as breeding stock were classified into five grades depending on age and presense of disease symptoms, and recommendations for mating partners were assigned as follows:

Grade:

A:

Age: Over 2.5
Syringomyelia: Absent or less than 2mm central canal dilatation in the C2-C4 region only
Recommended Class to Breed With: A, C, D

C:

Age: Under 2.5
Syringomyelia: Absent
Recommended Class to Breed With: A (Re-scan after 2.5 years)

D:

Age: Over 2.5
Syringomyelia: Present but asymptomatic OR Unknown (dogs without MRI scans)
Recommended Class to Breed With: A

E:

Age: Under 2.5
Syringomyelia: Present but asymptomatic
Recommended Class to Breed With: SHOULD NOT BE BRED

F:

Age: Any
Syringomyelia Symptoms: Present and symptomatic
Recommended Class to Breed With: SHOULD NOT BE BRED

In October 2010, Dr. Clare Rusbridge reported the following results using the above recommendations:

1. Grade A x Grade A produced 75.9% offspring without SM (24.1% SM positive)
2. Grade A x Grade D, E, or F produced 41.9% offspring without SM (58.1% SM positive)
3. Grade A x ? (dogs without MRI results) produced 50.0% offspring without SM
4. Grade D x Grade D, E, or F produced 0% offspring without SM (100% SM positive)

• puppies
• Breeding
• Risk
• Disease
• Syringomyelia