What is Chondrodystrophy and Intervertebral Disc Disease, CDDY/IVDD, Type I IVDD
Chondrodystrophy (CDDY) refers to the "long and low" body shape characteristic of many dog breeds including Dachshunds and Corgis. Recently, a mutation was discovered that not only predicted the chondrodystrophic body shape, but increases the risk of Type I intervertebral disc disease (IVDD or "slipped disc."). A dog with one or two copies of this mutation has an increased risk of developing IVDD compared to a dog with zero copies. Its effect on body shape is slightly different--a dog with one copy of the retrogene is likely to have longer legs than a dog with two copies, but shorter legs than a dog with zero copies. We measure this result using a linkage test.
Please note that this mutation is extremely common in many small and chondrodystrophic dog breeds. In these breeds, this mutation may not be the strongest predictor of IVDD risk compared to other genetic or environmental factors; further, no genetic mutation is a guarantee of clinical disease. There is active research going in to the frequency of this mutation within particular breeds and how it impacts IVDD risk. It is likely that other genetic factors that can contribute to IVDD risk, as well as environmental factors. In addition, many chondrodystrophic dogs do NOT have this mutation--another even more common FGF4 retrogene on canine chromosome 18 also drives a chondrodyplastic body type, but is not associated with IVDD (described in Parker et al 2007).
Citations Embark & Brown et al 2017, Batcher et al 2019
How do I know if my dog will develop this health condition?
Research indicates that dogs with one or two copies of this variant have a similar risk of developing IVDD. However, there are some breeds (e.g. Beagles and Cocker Spaniels, among others) where this variant has been passed down to nearly all dogs of the breed and most do not show overt clinical signs of the disorder. This suggests that there are other genetic and environmental factors (such as weight, mobility, and family history) that contribute to an individual dog’s risk of developing clinical IVDD. Signs of IVDD include neck or back pain, a change in your dog's walking pattern (including dragging of the hind limbs), and paralysis. These signs can be mild to severe, and if your dog starts exhibiting these signs, you should schedule an appointment with your veterinarian for a diagnosis.
- In breeds where this variant is extremely common, this genetic health result should not be a deciding factor when evaluating a dog for breeding or adoption purposes.
Dr. Kari Cueva
Veterinary Geneticist at Embark
What actions can I take?
- Please tell your veterinarian about your dogs result.
- Follow veterinary advice for diet, weight management, and daily exercise.
- Ramps up to furniture, avoiding flights of stairs, and using a harness on walks will also help minimize some of the risk of an IVDD event.