Hansen's Type I IVDD, Intervertebral Disc Disease
Chondrodysplasia (CDPA) is a genetic disease causing abnormal growth of cartilage and early changes in the structure of growth plates. The affected dogs are generally characterized by a normal sized trunk and short limbs. Dogs with chondrodysplasia (CDPA) have short legs; this phenotype is characteristic for many breeds such as Welsh Corgi and Dachshund.
Chondrodystrophy (CDDY) is caused by a separate mutation, also includes a short-legged phenotype as well as abnormal premature degeneration of intervertebral discs leading to susceptibility to intervertebral disc herniation (IVDD).
The inheritance of CDDY is semi-dominant (dogs with 2 mutations are smaller than dogs with 1 mutation. However, the inheritance of IVDD is autosomal dominant meaning that 1 mutation is sufficient to express IVDD phenotype.
Genetic testing for these mutations can help breeders to determine if CDDY is present and to identify dogs at risk for IVDD. In breeds where both types of mutations are present, breeders can benefit from test results to implement breeding strategies to reduce incidence of CDDY, while keeping the short-legged phenotype caused by CDPA.
American Cocker Spaniel, Australian Shepherd, Coton de Tulear, French Bulldog, Nova Scotia Duck Tolling Retriever, Welsh Corgi Cardigan, Welsh Corgi Pembroke,
Gene and mutation
FGF4 retrogene insertion into chr. 18 (CDPA) a chr.12 (CDDY + IVDD)