Correlation analysis of clinical features and genotype in dogs with intervertebral disc degeneration

Abstract

Most modern pet species have awide breed variability. The genetic aspect plays a signif-icant role in the development of individual pathologies. A retrogen encoding fibroblast growth factor 4 (FGF4), when inserted into the chromosome 18of dogs (CFA18), leads to chondrodysplasia, phenotypically mani-festing itself as shortened limbs in dogs. The incorporation of the FGF4 retrogene into chromosome 12 (CFA12) leads to a similar phenotype, but associated with an increased degeneration of the intervertebral discs. Although many retrogens are considered “silent”pseudogenes, the FGF4 retrogene in cases of chondrodysplasia and chondro-dystrophy is transcriptionally activated and leads to hyperactivation of the fi-broblast growth factor 3 receptor (FGFR3). Mutations are dominant, but links with spinal problems have been identified only for one, where the retro-gene is integrated into chromosome 12. Thus, dogs with the phenotype of short limbs are at risk for degenerative disease of the intervertebral discs, however, the disease recorded among animals is not related to chondrodystrophoids. The genetic predispo-sition of dogs of chondrodystrophoid breeds to degeneration of intervertebral discs is not a pathognomonic criterion for its presence. The study included genetic tests of dogs of different breeds, which were examined for compression myelopathy as a result of degeneration of the intervertebral discs. During testing, the purpose of which was to find correlation, the corresponding pedigree predispositions and clinical mani-festations of degenerative diseases of the intervertebral discs among 20 dogs (14 chondrodystrophoid and 6 non-chondrodystrophoid) wereconfirmed, in 14 cases (i.e. 70%) discogenic compres-sion was revealed during tomography.