Chondrodystrophy (CDDY) & Chondrodysplasia (CDPA) Suseptibility to Intervertebral disc disease (IVDD)
Chondrodystrophy (CDDY), is a general term used to describe a genetic skeletal trait affecting the development of cartilage growth plates and generally characterized by a normal sized trunk and shorter than normal limbs.
Chondrodysplasia (CDPA) refers to abnormal cartilage growth and bone development. Many dog breeds like Dachshund, Bulldog, Corgi, Pug, French Bulldog, Bassett Hound, Pekinese, Lhasa Apso, Shih Tzu, Beagle… are defined as having short limbs. Other skeletal characteristics sometimes associated with chondrodysplasia in dogs are a lower jaw that may protrude further than normal, or an unusually short upper jaw or over under bite with crooked teeth. Bowed front legs, a crooked spine or some breathing problems are also often found to be a problem. In 2009, a discovery found that in dogs CDPA is caused by autosomal dominant FGF4 insertion on chromosome 18 promoting short-legged phenotype. Fibroblast growth factor-4 (FGF4) is s common protein involved in early development on cartilage and bond length.
In 2017 researchers in the Bannasch Laboratory discovered a second FGF4 insertion on chromosome 12 is associated with CDDY in dogs with short limbs as well as the propensity to developmental InterVertebral Disc Disease (IVDD).
Intervertebral disc disease IVDD is described as premature calcification of the nucleus pulposus. Nucleus pulposus is the inner core of the vertebral disc made-up of water, and network of collagen fibers. The elastic structure works as a cushion to allow flexibility of the vertebral column to withstand forces of compression and torsion without damaging the disc. Premature calcification of the nucleus pulposus causes the disc to be less able to adjust to compression. The nucleus pulposus can herniate through the protective layer of annulus fibrosus, leaking out of the disc space and inflaming the nerve roots next to the disc causing severe pain and neurological dysfunction or myelopathy. IVDD is a degenerative disease and premature calcification can start in dogs less than a year old.
Animal Genetics offers testing for both CDDY and CDPA mutations. Current list of dogs with either variant in both CDDY and CDPA is not complete and will expand as more testing is complete. CDDY is considered a semi-dominant trait meaning dogs with 2 copies of the CDDY mutation are smaller than dogs with 1 copy of the mutation. CDPA is a dominate trait meaning dogs only need a single copy to be affected and susceptible to IVDD. Dogs that test positive for both CDDY and CDPA have shorter legs. Research is ongoing to determine if dogs that test positive for CDDY and CDPA are more prone to IVDD then dogs that test positive for only IVDD. Testing can help identify if the dog is at risk for IVDD by distinguishing short legged dogs with CDPA from those with CDDY.
Animal Genetics accepts buccal swab, blood, and dewclaw samples for testing. Sample collection kits are available and can be ordered at test now.
Test Is Relevant To the Following Breeds:
Basset Hound, Beagle, Bichon Frise, Cardigan Welsh Corgi, Cavalier King Charles Spaniel, Chesapeake Bay Retriever, Chihuahua, American Cocker Spaniel, Coton de Tulear, Dachshund, Dandie Dinmont Terrier, English Springer Spaniel, French Bulldog, Havanese, Jack Russell Terrier, Nova Scotia Duck Tolling Retriever, Pekingese, Pembroke Welsh Corgi, Poodle (Miniature and Toy), Portuguese Water Dog, Scottish Terrier, Shih Tzu.
Results For CDPA:
Animal Genetics offers DNA testing for Chondrodysplasia (CDPA). The genetic test verifies the presence of the mutation and presents results as one of the following:
|NN/NN||Clear||Dog test negative for CDPA mutation.|
|CDPA/n||Affected||Dog test positive for 1 copy of CDPA and will pass on a copy 50% of the time. Dog will be short legged.|
|CDPA/CDPA||Affected||Dog test positive for 2 copies of CDPA and will pass on a copy 100% of the time. Dog will be short legged.|
Results For CDDY:
Animal Genetics offers DNA testing for Chondrodystrophy (CDDY). The genetic test verifies the presence of the mutation and presents results as one of the following:
|NN/NN||Clear||Dog test negative for CDDY mutation.|
|CDDY/N||Affected||Dog test positive for 1 copy of CDDY and will pass on a copy 50% of the time. Dog will be short legged and at risk for IVDD.|
|CDDY/CDDY||Affected||Dog test positive for 2 copies of CDPA and will pass on a copy 100% of the time. Dog will be short legged and at risk for IVDD.|