We do not recommend the use of the UC Davis "DNA Test" for IVDD
Breeding schemes for intervertebral disc disease in dachshunds: Is disc calcification score preferable to genotyping of the FGF4 retrogene insertion on CFA12?
Our results show that the FGF4 retrogene insertion on CFA12 is not a valid risk indicator on its own. Relying on the DNA test will have an irreversible effect on the Dachshund breed excluding almost all dogs from breeding. Thus, using calcification status remains the most reliable breeding scheme for disc herniation in Dachshunds.
Phenotypic Effects of FGF4 Retrogenes on Intervertebral Disc Disease in Dogs. Bannasch et al 2019. [Open Access] In this study, which included 393 Dachshunds from the UK, USA and Switzerland, 93% had 2 copies of the 12-FGF4RG (CDDY)
mutation. UK/US Dachshunds had a mutation frequency of 0.98. This suggests the CDDY mutation is largely "fixed" in the breed. 148 Dachshunds in this study were surgically treated for IVDD and they
had a CDDY mutation frequency of 0.99.
"The main contributor to disc calcification was the presence of 12-FGF4RG. The odds of disc calcification increased with increasing number of copies of 12-FGF4RG. When compared to dogs with one copy of 12-FGF4RG, dogs with two copies had 2.5 times greater odds of disc calcification. At least 1 calcified disc was observed in 90.5% of Dachshunds and the breed had significantly higher odds (2.53) of disc calcification than other breeds.
"The high allele frequency of 12-FGF4RG among chondrodystrophic breeds, such as Dachshunds and French Bulldogs, precluded the calculation of a relative risk (of IVDD surgery)." This suggests that, because the mutation is so fixed in Dachshunds, it is of little use as a predictor of IVDD surgery.
Pathologic Features of the Intervertebral Disc in Young Nova Scotia Duck Tolling Retrievers Confirms Chondrodystrophy Degenerative Phenotype Associated With Genotype. Murphy et al 2019. [Abstract] This paper confirms that the CDDY mutation is associated with disc degeneration. We know that Dachshunds' discs calcify and degenerate at a much younger age than non-dwarf breeds. The fact that around 75% of Dachshunds do not suffer from herniated discs confirms our view that using this DNA test in our breed is largely a waste of money.