The relationship between radiographic disc calcification score and FGF4L2 genotype in dachshunds

Background: The relationship between radiographic disc calcification score and FGF4L2 genotype has been reported in only a small number of dachshunds. Hypothesis: A genotype with either 0 or 1 FGF4L2 copy will be associated with a lower number of calcified discs (lower K-n) compared with a genotype with 2 FGF4L2 copies. Animals: Dachshunds registered with the Norwegian or Finnish Kennel Clubs for which both K-n and FGF4L2 genotype are known (n = 407). Methods: Retrospective study (2012-2024). The frequency and percentage of dachshunds within each K-n group (K0, K1/2, K3/4, K5+) by FGF4L2 genotype (FGF4L2/FGF4L2, N/FGF4L2, N/N) were reported. The K-n distribution differences among genotypes were analyzed by the Cochran-Mantel-Haenszel test in SAS 9.4. Significance was defined as P <.05. Results: A difference in K-n distribution was found between dachshunds that have 0 or 2 FGF4L2 copies. However, no difference was found in the K-n distribution between dachshunds that have 1 or 2 FGF4L2 copies. Conclusions and Clinical Importance: Most dachshunds with 1 FGF4L2 copy have radiographic disc calcification scores that are associated with substantially lower risk of symptomatic disc disease. Radiographic disc calcification scores are similar in dachshunds with 0 and 1 FGF4L2 copies. Given the high allele frequency of FGF4L2, breeding to produce progeny with 1 FGF4L2 copy is expected to be a more achievable short-term goal for dachshund spinal health breeding programs than breeding for 0 copies. It is recommended that both K-n and FGF4L2 genotype status be considered when choosing dachshund breeding stock.