Chondrodysplasia

Skeletal dysplasias are diseases that affect the bones and cartilage, including chondrodysplasia, which produces an abnormally short stature.

Symptoms

Affected dogs usually have curved forelimbs, carpal valgus or outward deviation of the hands, shortening of the vertebral bodies, delayed ossification of the carpal bones and widening of the metaphyses. The muscles of the pelvis and thigh are underdeveloped and hip dysplasia may occur.

Disease Management

Should your dog show any symptoms, such as short limbs or disproportionate growth, you should see your veterinarian for evaluation.

Genetic basis

This disease follows an autosomal recessive mode of inheritance. Autosomal recessive inheritance means that the dog, regardless of sex, must receive two copies of the mutation or pathogenic variant to be at risk of developing the disease. Both parents of an affected dog must carry at least one copy of the mutation. Animals with only one copy of the mutation are not at increased risk of developing the disease, but may pass the mutation on to future generations. Breeding between dogs carrying genetic variants that can cause disease, even if they do not show symptoms, is not recommended.

Technical report

Chondrodysplasia affects endochondral ossification, which is the process of bone tissue formation in the epiphyseal plates. These plates are growth zones present in the long bones and are made up of cartilaginous tissue. Alterations in genes involved in bone development, such as genes involved in the production of extracellular matrix components and genes that regulate growth, are particularly important in this type of skeletal pathology. In these pathologies, genes coding for different types of collagen (COL9A1, COL9A2, COL9A3, COMP, MATN3, COL2A1, COL11A1 and COL11A2), proteoglycans such as perlecan and aggrecan, as well as hormone receptors such as parathyroid hormone receptor 1 (PTHR1) and receptors for growth factors such as fibroblast growth factor receptor 3 (FGFR3) may be affected. In this study, the pathogenic variant c.2083C>T in the ITGA10 gene was analyzed. This gene codes for a protein that belongs to the integrin family and is located on the cell surface. This protein mediates the binding of cells to the extracellular matrix and, in addition to having a structural function, may participate in cell signaling processes. In the study by Kyöstilä et al. it was observed that the c.2083C>T or p.Arg695* mutation produces an afunctional truncated protein.

Most affected breeds

Karelian bear dog
Norwegian Elkhounds

Bibliography

Kyöstilä K, Lappalainen AK, Lohi H. Canine chondrodysplasia caused by a truncating mutation in collagen-binding integrin alpha subunit 10. PLoS One. 2013 Sep 25;8(9):e75621.

Smit JJ, Temwitchitr J, Brocks BA, et al. Evaluation of candidate genes as a cause of chondrodysplasia in Labrador retrievers. Vet J. 2011 Feb;187(2):269-71.