A form of recessive chondrodysplasia described in three breeds, in particular the Norwegian Elkhound and the Karelian Bear Dog, with extension of the test to the Chinook. It produces dwarfism caused by altered development of the growth cartilage, with shortened limbs and skeletal deformity. Affected animals show an abnormal growth pattern from an early age.

Norwegian Elkhound, Karelian Bear Dog and Chinook. Carrier frequency of 24 % (156 Finnish Elkhounds) and 8 % (287 Karelian Bear Dogs) in the cohort of Kyöstilä et al. (2013); there are no consolidated figures for the Chinook. The molecular variant is the same in the three breeds.

- Short limbs with a trunk of relatively preserved proportions
- Skeletal deformity of the limbs
- Abnormal growth evident from an early age
- Reduced size compared with the breed standard
- No severe systemic involvement beyond the skeletal phenotype

Chondrodysplasia of the Norwegian Elkhound and the Karelian Bear Dog was initially described by Bingel and Sande (1982). Kyöstilä et al. (2013), using a GWAS in 9 affected and 9 control Norwegian Elkhounds, mapped the locus to a 2 Mb interval on CFA17 and identified in ITGA10 a nonsense mutation in exon 16 (c.2083C>T, p.Arg695*) that segregated with the disease in both breeds: carrier frequency of 24 % in the Norwegian Elkhound and 8 % in the Karelian Bear Dog. Donner et al. (2016), using panel screening, detected the same variant in the Chinook and proposed a plausible molecular explanation for its chondrodysplasia; OMIA lists the Chinook among the breeds with the documented variant, although clinical confirmation in this breed is more limited than in the Norwegian Elkhound and the Karelian Bear Dog.

- Test breeding animals before mating
- Do not cross two carriers: 25 % of the litter would be affected
- A carrier may be crossed with a clear animal; test the offspring intended for breeding
- In the Chinook, recommend additional caution due to the breed's lower molecular characterization

Differential diagnosis with other canine skeletal dwarfisms (FGF4 chondrodysplasia, reticular dysplasia, juvenile hypothyroidism). Radiography and growth assessment are useful for phenotypic diagnosis. Genetic testing is decisive in well-characterized breeds.

1. Kyöstilä K et al. (2013) Canine chondrodysplasia caused by a truncating mutation in collagen-binding integrin alpha subunit 10. PLoS One 8(9):e75621. PMID: 24086591
2. Donner J et al. (2016) Genetic panel screening of nearly 100 mutations reveals new insights into the breed distribution of risk variants for canine hereditary disorders. PLoS One 11(8):e0161005. PMID: 27525650
3. OMIA:001886-9615. Chondrodysplasia, disproportionate short-limbed, ITGA10-related in Canis lupus familiaris. https://omia.org/OMIA001886/9615/